I dabbled a little with ASP in college, but now work mostly in PHP (bits 'n' bobs). I find PHP sticks in my head easier that ASP ever did. However, speaking to 'Dad' (he's a programmer) he said he found ASP easy to learn because of a background in a few languages with similar syntax's. I guess what I'm saying is, go for whichever you feel most comfortable with learning.
Whichever you choose though, take your time learning it, and don't expect to make eBay overnight!