Lamisil AT
"This is the only medication I'd use or recommend for treatment of Tinea cruris (jock itch).  I've tried many different medications, and no other works nearly as well.
The main benefit is once-a-day application, and a one-week treatment time.

I've used Lamisil AT in cream, gel, and spray form.  I highly recommend the latter.  The problem with the gel and cream is that it's difficult to ensure adequate coverage without going through the product very quickly.  You will end up buying at least a second tube before the treatment has concluded.

The Lamisil AT spray goes MUCH farther.  Just put on a pair of vinyl gloves to help spread it around after spraying.  One spray bottle should be all you need.  Don't just spray; spray and spread."