Spring is finally available through Maven repositories for final releases, milestones and snapshots, and they are adding the sources too! Ben Hale has listed the repositories that you need to have into account.
- final releases available through central maven repo (no need to do anything at all)
- milestones through http://s3.amazonaws.com/maven.springframework.org/milestone (browse)
- snapshots through http://s3.amazonaws.com/maven.springframework.org/snapshot (browse)
I personally would like to see the milestones in the central repository as it makes life easier for users as many other projects do.