Poker Tools
Equity Calculator (Beta)
NOTE: This tool sometimes works by sampling a large number of hands, so it's subject to statistical error in the results. Barring a freak run, however, the results shouldn't be off by more than one- or two-tenths of a percent.
Holdem Equity Calculator with Hand Ranges (Beta)
This tool is down for maintenance. In the meantime, you can use PokerStove.