Feature branches support has got significant improvements in this EAP build. Now you can configure right in VCS root what branches you want to monitor in a build configurations.
The syntax of branch names specification is similar to checkout rules:
Once you define a branch specification, TeamCity will start to monitor these branches for changes. If your build configuration has VCS trigger and a change is found in some branch, TeamCity will trigger a build in this branch.
You'll also be able to filter history, change log, pending changes and issue log by branch name. Also branch names will appear in custom build dialog, so you'll be able to manually trigger a custom build on a branch too.