PSD to HTML services are companies that offer to convert the image you've designed in Photoshop to a web page. (They'd probably be happy to take images from other programs too.) There's a big list of them
here. They seem to charge $150-300 for the first page, and about half that for subsequent pages. It's worth stressing that all they are doing is converting your file to HTML - you have to do all of the design work. (So make sure it's right.

)
I read an article a while ago (and that I can't find now) that said some of these services are pretty good: they turn around jobs on time and give fairly lean and valid markup. Others, though, are apparently more dubious. I'd Google interesting-looking companies and see what others have to say before committing.