There is a new site that I came across this week that is dedicated to Lightroom presets (I LOVE Lightroom), it's call Presets Heaven.
Though it has been in existence for just a couple weeks now, they have already put a lot of presets out there, so be sure to check them out.
Back in July I did a post that listed where you could get a few hundred free Lightroom presets, one of those resources, ReallyJapan's Darkroom dropped me an email letting me know they have posted a new set of Cinematic presets that you can download here.
And lastly, probably the single best Lightroom resource out there is Matt Kloskowski's Lightroom Killer Tips, Matt adds free presets pretty much weekly (along with a ton of other Lightroom information), so be sure to bookmark his blog.
Have a great weekend!