A list of  5 must-have iPhone libraries that we use at tty.nl for our iPhone dev needs:

#1 ASIHTTPRequest

The network API of Apple’s Cocoa Touch framework is not a pretty sight. It’s verbose and hard to put into use. The ASIHTTPRequest library by All-Seeing Interactive is high quality wrapper around the CFNetwork API that makes http communication trivial to implement. Love it!

#2 Json-framework

REST & JSON are here to stay. (Bye bye SOAP, won’t miss you!). The json-framework library enables your killer iPhone app to parse & generate strict JSON.

#3 Touchcode

Cocoa’s NSXML API is much too complex for the 95% of the use cases. For that 95% you should just use touchcode. It’s based on the Open Source libxml2 and supports most XPATH queries.

#4 Pinch analytics

Pinch analytics is best described as Google Analytics for your iPhone app. It allows you to track the amount of unique users, the time spent per user, device types and much more. And just like Google’s package it’s totally free.

#5 RegexKitLite

I was shocked to discover the Cocoa Touch framework doesn’t support Regular Expressions out of the box. No worries though: RegexKitLite allows you to continue to use your carefully crafted regular expressions.