Best Way to Sync iCal OS X 10.5 w/Android and Windows?

[im_to_hyper]

Here's the deal. I've been strictly an Apple user with Apple products for quite awhile and now the cards have been dealt and I have to deal with them.

• I have a PowerMac G5 running 10.5.8, a small Toshiba laptop running Windows 7, and a T-Mobile G2 running Android 2.2.
  
• (In an ideal world I would have a MacBook Air and iPhone instead, and use MobileMe.)
  
• Now: I want to be able to keep my calendar sync'd across all three relatively easily. Is this in any way possible?
  
• I have Office 2007 on the PC and 2008 on the Mac (maximum version for the Mac) and just Google's calendar.
  
• I have a Gmail account as well... is there a way to make this all work somehow and put the pieces together?