What is so good about ASP?

the question's in the title... :)

I think it comes with IIS. It's server-side, simple, and reasonably powerful.

IIS? what's that? and what do you have to install to use it (ASP)?

IIS is the Internet Information Services, a webserver from Microsoft. I've never tried it myself. I've heard that it's rubbish, but in Linux circles, it's quite possible that people have said that just because it's from M$. IIS is not free; in fact, it's rather expensive. If you're looking for a free ASP.NET server, try Apache with mod_mono if you're running *nix, or, if you're just developing, try XSP. I wouldn't recommend XSP for public hosting.