A snapshot repository won't behave how you think it will behave. I recommend not providing one.
As a developer you want your code base to be in a known configured state. Having a snapshot repository will mean that Maven will pull in a new snapshot occasionally (you have some control over when they might be) and if that snapshot is SNAFU then you have just stopped that developer from being productive. If a developer wants a snapshot let them pull your code down and built it themselves, then if the code is SNAFU they can choose a previous revision from source control to use instead. Since you are talking about a sourceforge project then you are providing an open source, so you are better off deploying your releases to central. Your users will thank you for not slowing their build times down with your custom repo.
