[humblejohn]

I didn't know where to post this. I am a complete newbie to IM. I have tried to download several programs like Yahoo Messenger (which wouldn't download! I would like to send messages from my pc to friends cellphones. I was told that you could do that with some of these programs. I can also send IM's via my cellphone (typing takes forever).

What is the difference between say, AIM and just sending IM's from you cellphone(other than the convenience of the former)?

Am I charged more if I send from PC to cellphone? Is there any other way to go direct from pc to cellphone without having to download a messaging program?
Confused and thanks in advance.