To be more specific,
1. Install Python 2.6
2. (optional) Learn Python 3.0 syntax, and use it in Python 2.6.
It's been confusing, I admit; people hear about Python 3.0 and naturally wonder if Python 2.6 is now obsolete. No, Python 2.6 is specifically designed to make a smooth transition by accepting both Python 3.0 and 2.5 syntax.
The problem with installing Python 3.0 right away is that it will take a while before all the juicy third-party modules are available for 3.0. They should be available immediately for 2.6, though, since 2.6 can run them exactly as 2.5 does.
If you learn and use Python 3.0 syntax, then the code you're writing now in Python 2.6 will work in 3.0 in the future when your third-party modules are ready and you want to convert.
And if you'd rather ignore it all? That's fine, too. The differences are really pretty slight, and if you put off updating all your Python code for a year or two, it will be a very minor endeavor.
In short, it's really nothing to lose sleep over. And you absolutely don't need to hold off on learning Python until the situation is "more stable" - Python 2.6 provides you with a stable platform right now that bridges Python's past and future nicely.