Mobile Me problems

Ok let me first say, I am not a computer geek, in fact I'm a compudiot. I have an iphone that is unlocked (using tmobile) and I have a g4 powerbook which is about 4 years old, but is updated (latest os) and still runs great. So I want to use mobile me and have tried to update my phone, and it won't work. I also can't update my computer because it says I don't have enough spaceon some drive. It then asks me if I want to restore the phone (which would relock it I think). My phone isn't working that great anyway. There are alot of videos that I can't watch (there's just a little icon that looks like a lego with a question mark on it) and I still haven't figured out how to fix the edge issue. (as a side note, youtube works fine when I'm using wi-fi). I've seen the directions for fixing the edge issue, but I need it broken down kindergarten style... Can anyone help with all these issues?