I uploaded an Ant bundle to the review's section of the bundle repository a couple of months ago. There have been a few tweaks but it's now stable. I'm looking to getting it bumped up to the main repository so am canvasing here for some feedback.
http://macromates.com/svn/Bundles/trunk/Review/Bundles/Ant.tmbundle/
On top of the obvious build and run commands it's main features are integrated help, auto completion, document validation, and - the handiest for me - build target selection from a dialog pop-up, bound to ⇧⌘B. As Ant's a build system, and therefore language independent, you will have to configure the commands by adding the scope/s of your languages of choice, alongside possibly setting up an environmental variable to target your build.xml file of choice.
Anything that helps/improves/patches, is more than welcome.
Cheers, Simon