Can I use the music found on this site for <project-X> ?

Legally speaking video game music remixing is rather a grey area. However, the C64 remixing community is a very friendly one, and the general feeling is that as long as you're not using the tunes in a commercial fashion, or failing to respect the wishes of the artists you won't get in trouble.

That being said, the tunes are still copyrighted, often by the composer/performer or their publisher so if you want to do right (and you should) please check with the remixer/arranger and composer for each track before you use it. You can click the names in the 'arranger' column on Remix.Kwed.Org to get in touch with the performing artists by e-mail.

Composer copyright for the original chiptunes is a bit harder to navigate. However, Chris Abbott over at C64Audio.com administers the intellectual properties for a lot of the 'big name' C64 SID composers as well as a few others, so to make sure you're covering all bases, please check with him as well (he can often informally advise about other copyrights too). You can reach Chris through the "Contact Us!" link on http://www.c64audio.com/.