This is probably the link you're referring too. It doesn't hurt to repost it since this question comes up so often.
Fear not! I harvested these from the old forum:
http://www.mediafire.com/?zodmyogmkej
I think it's safe to assume that the original authors still don't mind people using them.
The best place around here to find tilesets is the Development Showcase (http://nifflas.lpchip.nl/index.php?board=26.0) thread. Many people post their public tilesets there. This thread (http://nifflas.lpchip.nl/index.php?topic=2621.0) in particular contains a ton.
Edit: I've asked a lot of people for permission to use/modify tilesets. The authors who responded were all very nice to me. When an author doesn't respond, a lot of them have disappeared, the policy on getting permission (http://nifflas.lpchip.nl/index.php?topic=2565.0) allows some leniency.