Second, you don't need to jailbreak in order to have more than 144 apps. Your iPhone/iTouch can handle more than that, just that you won't see the icons. However, if you swipe to the left from your home screen and search for the app you want, you will find it.
However, once 3.1.3 can be jailbroken, you can always get "Categories".
I am in a dead area where my phone does not work. All I use it for is apps mostly art photography related. I have wifi at work and I use this more than I do my computer.
Read up on it, and get on with it! I only got my iPhone this week and have jailbroken it already, and am loving it! Just follow guides carefully and you'll be fine.
jailbreaking isn't really difficult. Just follow one of the thousand tutorials around the web and you will be cool. Honestly if you can read and click buttons you probably don't even need a tutorial.