Craigslist Pro+ by Escargot Studios is an excellent native Craigslist application for the iPad. Recently Craigslist officially licensed this application. I have tried several other Craigslist applications on my iPad and this is by the best of the bunch.
Some of the features of the application include:
If you enjoy Craigslist either as someone who sells on Craigslist or someone who buys on there and you are using an iPad this the app you want. Craigslist PRO+ is an iPad only applicatoin, it is only a $1.99 in the App Store.