I have ADD, too, and have found the following to be helpful. Maybe some of them will help you. I avoid "songs" and keep entirely to instrumental music when I'm trying to work.

iSerenity has about 30 sounds including pure white noise and is free to use while you're online. I don't know if you can capture the sound and save it to disk. It's great to use to see which sound actually helps you. I thought I wanted white noise but finally settled on the shower.

http://www.iserenity.com/environments.htm

You might consider Chinese music. While having lunch at a Chinese restaurant I realized that the background music was calming and not intrusive. There's an archive of traditional Chinese music at the Internet Chinese Music Archives site with names like High Mount Flowing Water etc--it relaxes me just to read over the list of titles. You can explore on this site and find more titles on other pages, but this page is great to start with.

http://music.ibiblio.org/pub/multimedia/chinese-music/html/traditional.html

Sometimes you might want to have something with a fast tempo going in the background to keep you focused on work and keep you on track. You can find techno, electronic, and ambient music in different places; explore these for starters. Some of them are free downloads. You might also like classical guitar or lute, and baroque music (instrumental, not the songs). The Travis Castillo site has "minimal" tracks--nice to have going in the background, and not intrusive, but it helps block out other things.

http://www.traviscastillo.com/ http://magnatune.com/genres/electronica/ http://magnatune.com/genres/classical/

As the parent of a college student, I've learned that there's software that lets you capture streaming audio, but don't know what it's called.

HTH,
Glenda