Main thing is finding a CPA who has some experience with the type of business you're running. Freelancer, Corporation, etc...find a CPA who can speak the language.

It's less an issue now, but 10+ years ago, there were a lot of CPAs who didn't have much/any experience with internet-based businesses and so they weren't familiar with some of the additional bits to take in to account.

As for affiliate sites...I probably made a grand total of 50 cents from them...total. :P