Syntaxee is super simple free Google Wave gadget, that lets you embed syntax highlighted code right in your blip. Gadget supports 13 programming languages C++, C#, css, Delphi, Pascal, Java, Javascript, PHP, Python, Ruby, SQL, Visual Basic, XML/HTML thankfully to Alex Gorbatchev's core. Please keep in mind that Syntaxee (like the whole wave) is in early state of development so it may have some bugs, don't worry we'll kill them all. Please send us any suggestion you have and report issues. Oh, and one more thing, this project is fully non-profit, just a hobby.
System requirements: Google Wave account :)
Installation
Press the puzzle icon 
on the tool bar of your wave, and paste Syntaxee's gadget link presented below to place gadget in your wave.
You can also use extension installer to add this gadget to your toolbox. Press the installer 
icon and paste this url.
Updating
Latest version automatically overwrites previous one so there's no need to bother you with this. Nice isn't it? :)
Maciej Król