I'd recommend mozilla - and a whole bunch of associated libraries...
Quick google turned up this:
IBM software downloads - Trials and demos search results
I've installed it in the past but found there is a lot of leg work to get it to work and function like a browser would normally, straight out of the box.
I hope someone can point you strait to a decent how-to, I avoid having to do this because what seem like such a simple task is so painful on AIX.
If you could post back how it works out for you and a step by step process I'm sure a lot of people would thank you, as would I.
Good luck.