Learning arabic on your own is a challenge. I chose to supplement the Kitaab fi tacallum al-arabiya series with MSA Vocab Clinic to get up to speed a little faster. It gives good pronounciation help, and the word lists makes bus rides a lot more fun... 
 
This is a nice tool for beginners and intermediate level learners of MSA, but if you've been studying for a while you will find this a bit frustrating. The 4000 words utilized are good, but they won't take you to the next level. The lists are good, but it would be nice to be able to make your own. A section of Arabic proverbs would be very useful as well, as knowing them makes a real difference when dealing with native speakers. I would pay $25 for this, but no more. 
 
I agree, the CDs are a much needed help, since it would be impossible to pronnounce the Yoruba tones without the help of a native speaker. However, the design of the book is really poor and confusing. I have found several spealling mistakes in English and Yoruba. And the grammar explanations are very hard to understand.Unfortunately there are not many Teach Yourself Yoruba books that are worth it. This one at least provides basic vocabulary and pronounciation skills. 
 