There's also Can You Run It : Can You Run It?
Bear in mind it's not 100% accurate, actually check what it says,
Example: I have a Dual Core 2.0Ghz Processor. According to the Sims 3 specs, you need EITHER a 2.4Ghz single core, or a 1.8 GHZ Dual. According to CYRI I fail, because my processor is less than 2.4Ghz, when in fact it's more than ample.