> Regular Expressions are a really powerful tool, and the absence of support for regular expressions in the iPhone SDK seems to be a glaring omission.

NSRegularExpression was added to the iOS SDK in 4.0.

Not available if you still aim to be 3.x-compatible (for iPhones and first-gen Touch), but 4.0 has been out for 9 months now, I think it's time to bury this one (note: you could still find NSRegularExpression insufficient or inferior to RKL, that's a different issue).