Is there an easier way to edit the syntax coloring than opening up the package contents and editing files by hand?
No, not currently. You can place files in your local library to override the ones shipping with TM, so you don't edit the original ones (which will be replaced by updates).
Apologies to ask about something that appears to have already been covered but I guess I didn't sign up for the mailing list quickly enough! I have found that I can make some changes to the coloring for obj-C (/Applications/TextMate/Contents/SharedSupport/Bundles/c.tmbundle/ Syntaxes/ObjectiveC.plist) but how do I get to the settings for elements other than foregroundColor and backgroundColor? Where are the settings for font attributes for comments and such?
Also what can be placed in the ~/Library and where?
tia! jeff