Spring Integration releases and snapshots are deployed to our S3 repositories (the ones that back the SpringSource Enterprise Bundle Repository). You can browse the full releases using our Bundle Repository application (http://www.springsource.com/repository/app), but since Integration is not GA yet you have to go through the S3Browse application (http://s3browse.com/explore/reposito...maven/bundles/). There is a "milestone" subdir there where you will find M5, and a "snapshot" subdir where the nightly builds go. There were some issues with the snapshot deployment in M4 and M5, but they seem to be working fine now.
Keep posting here and in JIRA if there are problems.
Here's my POM config for snapshot usage:
Change "snapshot" to "milestone" to get the milestone releases, etc.