Let's stipulate that most people who keep constant vigil over their investment accounts these days are either masochists or eternal optimists. They're also a bank's best friend. Financial institutions figure they can squeeze more money out of their customers, or at least make it harder for them to stray to other banks, if those customers are around-the-clock users. And sure enough, unlike some of the 'buy, try and toss' services that litter the various mobile-application stores, banking and investment apps have a way of becoming absolutely habitual. I recently tested the top mobile investing app on the iPhone, ETrade's Mobile Pro application, and, for those who need more basic finance help, also tried the most popular free banking application, from Bank of America. Bank of America's mobile app is good enough for basic household financial needs, but it lacks some of the nifty features offered on the bank's Web site. ETrade's app is stellar, though, to the point that investors can largely forget about hauling themselves to a PC to check their financial performance. I leaned on ETrade and it kindly agreed to fund an account with a few bucks so I could try my luck with trades. If I won big, ETrade would reap the windfall. (And if I picked poorly? Impossible! I roped my two youngest children into picking.) Before we got that far, though, we had to navigate the other parts of the service. Fortunately, ETrade makes great use of the iPhone's touch screen -- especially the application's menu, which other mobile software developers would do well to copy. (ETrade is working on a version for the BlackBerry Storm, but hasn't yet offered a release date.) The top of the screen shows four icons that scroll laterally to reveal 11 more. It shrinks to a small 'menu' icon when you're within one of those categories. All the major elements are here: indexes, quotes, portfolio recaps, market news and buttons allowing you to trade shares of any publicly held company. The functions within each category are enough to satisfy all but the most sophisticated traders, with perhaps one major exception: You can't yet trade bonds because, ETrade said, there was not enough demand for that to include it in the software's early version. Nor can you use the app to set up a new payee, if you wish to cash out. But the company said this policy protects users, because if someone snatches your iPhone while you're logged on, they can't transfer your funds to their bank account. To set up a payee, you must log onto ETrade.com. A few items from ETrade's Web site are missing from Mobile Pro, like video tutorials. On the other hand, your PC can't do this: Shake the iPhone at different moments and it will update a quote or clear your order ticket. (Last week I shook it while looking at our sinking portfolio value. No luck.) The app falls short of perfection in other ways, as iTunes reviewers are happy to point out. The Greek chorus complained, among other things, about bugs in a new feature intended to inform users when a stock hits a certain level. The company said this week the problem has been fixed, as have other problems that caused the app to crash. Overall, though, users give the app 3.5 stars out of five. In ratings, the only major stock-tracking app that rivals Mobile Pro is DailyFinance, from AOL. That application, which is also free, offers many of the same portfolio-tracking features as Mobile Pro, albeit in a slightly less slick interface. Bank of America's app, meanwhile, offers much less to shout about, but it is useful. You can view and pay bills with the service, which pulls existing billing information from your Bank of America online account. You can also see account balances and recent transactions, and transfer funds. Unlike its online service, Bank of America's mobile app does not show copies of recent checks, so unless you have a bankbook to help trace the check number, or a remarkable memory, you'll have no way of knowing who received your last $50. As with ETrade's Mobile Pro, Bank of America's mobile service automatically logs you out after a few minutes of inactivity, so you run less risk of exposing your financial information to phone thieves. Bank of America's mobile service, which is also available for BlackBerrys and T-Mobile's G1, mirrors the functionality available to Chase and Wells Fargo mobile customers, among others. Judging from the App Store reviews, where five-star reviews barely outnumbered one-star reviews for all three banking apps, borrowers regard these services with the ambivalence common to most realms of the bank-borrower relationship. Thank goodness the apps are free. Since you've made it this far, you might care to know how well my children did at picking stocks. In the middle of June, my daughter Juliana chose the Phoenix Cos. (she liked the name), which since then has risen just over 4 percent, to $1.73 a share. During that time, the Dow slipped about 1 percent. My son Luca picked Forest City Enterprises (for similar reasons), and it too has staged a bit of a rally, up about 5.5 percent, to $6.55 a share. Yup, my kids beat the Dow. And I've just decided what they're doing this summer for work. (STORY ENDS HERE. OPTIONAL SIDEBAR FOLLOWS.) QUICK CALLS -- The iPhone app Ocarina turned the device into a musical instrument played all over the world. Now iPhone musicians can expose their talents to worldwide judging, with Leaf Trombone, by the creators of Ocarina. Play the ridiculous-sounding instrument to torment or entertain others, or just get a good laugh at your own expense. The app ($1) just received an update allowing users to play duets. -- BlackBerry recently released the new Visor Mounted Speakerphone ($100), which, in addition to fielding calls, allows users to transfer music from their phone to their car stereo. -- The next 'Google phone' is on the way. Next week T-Mobile will begin taking orders for the myTouch 3G, the second device to run on Android, the software platform championed by Google. The myTouch ($200 with two-year contract) has a 3.2-inch touch screen, video camera and Wi-Fi, and will be released early next month. 