I've been using Linux distros for about 6 months now, Ubuntu, Granular are the ones I have the most experience with and neither of them gave me any problem getting online,they detected and set up everything automatically. I'm using Granular and windows XP pro on my computer right now, The only reason I am using XP at all is because I just can not find a couple Linux versions of programs I use in XP.
If you want to try a Linux I highly recommend Granular, it like most Linux versions is free to download. One draw back with Linux is that they are always releasing new versions and when a new one is out there are bugs that need to be worked out so I suggest you try a "stable" version, this is not a testing one.