As far as places to get maps, I would suggest www.broodwarmaps.net. I would imagine they'll have anything and everything you could possibly hope to find outside of battle.net. You can also find map packages where people just put a ton of maps in one file for you to download. You might try looking on google to find massive packs of 1000+ maps. Have you thought about making your own maps? I haven't done any map building for a while, but back when starcraft was big I got into it a bit, and from what I remember it was really quite easy. You can even take pre-existing maps and tailor them to your needs.

Welcome to the community, by the way! I don't think you'll find many people playing or talking about starcraft/brood war here these days, but Starcraft 2 will be big here, so I hope you stick around for the fun. If you feel like it, you can make a thread to introduce yourself here.