You do not need a local subversion repository. Subclipse works fine on network connections... not sure where you are getting lost, but it’s just like an SVN client built into Eclipse...it just works along side things like Delete and Rename in the IDE to take approprite SVN actions. If you are working in a project that is checked out under SVN control, you can right click on any file or editor and select Team and you’ll see all the available SVN actions you want to take.
Ok, I’ve got the three set up (Eclipse, PHPEclipse, and Subclipse). Do I have to have a local subversion repository? As far as I can tell, I do, since Subclipse does not do network connections. So if I have a branch in the MODx svn repository, how do I synchronize my local repository with my remote branch?
I do personally because PHPEclipse is open source and you’ll never see features available in a commercial only version (whereas PDT will never have the features Zend is offering in it’s commercial IDE plugin for Eclipse). If I want a specific feature, I can help code it (since I have some Java experience) by contributing it myself; something that would be much more difficult with PDT.
Do you guys find PHPEclipse better that PDT?
Once you do a checkout, all you need do is right click on the existing project and select Team --> Update to HEAD.

should have been in the project explorer perspective. It works fine. Thanks.