I really like this company Voxengo...I use their limiter and really like the way they operate...anyway, they have two free plugins..one is very useful for 303 users or anyone who individually tracks their mono drum sounds or sample sounds and wants a stereo effect afterwards. Also just for more mixing tools and options (haven't tried this yet with vocals though)

http://www.voxengo.com/product/stereotouch/



and another for "tagging" beats you want to sell, or other stuff you don't want stolen? I never do this but downloaded it anyway...beeeper

http://www.voxengo.com/product/beeper/



I'm going to repost this on the MPC forums too, just a heads up if anyone is over there too