What Messaging Interface works with both Apple and Microsoft

This is one of the most annoying aspects of Apple and why I hate their PCs and OS.  So my uncle changes to an apple...cause he knows the frigging guy who is the lead for Iphone or whatever.  Wank Wank, so he changes from the nice custom built PC I built him, beautiful with ASUS motherboard, yada yada, to a stupid Apple with Lepard OS or whatever the hell they call it.

I hate Apple...why?  Precisely, I can't chat with him unless I get an AOL account...how gay.  I hate AIM.  It's shitty software.

http://www.apple.com/macosx/features/ichat.html

Ok, so he probably uses ichat (I have to varify) but ichat doesn't allow you to add gmail, hotmail, or other friends.  Again, this is the pain in the ass factor of Apple...as it's always been, not open to the rest of the world.

Are there any messaging software we can both use without required a gay AIM account?  I want him to be able to use his stupid piece of crap Apple OS and still be able to chat with the rest of the world....Microsoft.  How can we do this...is there a few messaging apps that can collaborate between the two?

I wish Pidgin could but it doesn't.  This is so frustrating, I only want to chat but Apple does not make such a simple thing so easy.

We were using Messenger Live together (yea ok, so some people hate it but at least it works with the rest of the world!)....but now, I have not a clue about stupid Apple OS and how we can chat again....I'm NOT getting a piece of crap AIM account.  In fact why do people still use their piece of shit software?

Why do people isolate themselves by continuing to support Apple's OS.  It's not any better in terms of what it can do vs. Vista....it's all about the graphic card, etc.  I just don't get why people switch to the "pretty" aspect but then come to isolate themselves to that OS.  I just don't get it.  You can't install half the cool shit out there (at least at the time I wrote this) like slingbox, silverlight, and a ton of other stuff until they come out with an "apple" version...how lame and irritating is this for the Apple OS.  We have to accomodate for you because your OS doesn't have a lot of compatibility with the rest of the world out of the box.