I keep telling my sisteres that finding Argentinian torrents is next to impossible. Here's a list of sites, though, with some in Spanish (don't know how old it is). For anything anime/manga related I use, of course, Boxtorrents, for anything else I mainly use Isohunt, but then again, no local torrents. Sometimes a manga site redirects me to a specific tracker, but I don't keep track of them (hehe). Mininova is still arround, too. I'm about to register into a Spanish-speaking site, Portal Pirata (kyouneko, the usual drill) but I'm starting to think I've already registered somewhere else... I'll have to check some old mails.
Edit: Two other sites, similar to PP, you probably need to register to dl, not sure: PcTorrent - PctTracker. NOT worksafe, I tell you - heavy on the sex-side (which would be very interesting under different circumstances, mind you!)