I agree with Brian; it is a common practice (and I think a best practice) to ignore the "target" directories at the SVN level.
After a clean checkout and a standard Maven build, there should be no file in an "unknown" SVN status. Otherwise, there is a risk that someone will end up adding build artifacts to SVN. The other solutions (e.g. ignoring them at the IDE level) are not centralized, or require distributing IDE settings, which is not a good idea.
