How does one go about marking a major revision using the Subclipse plugin? I'd like to mark a project at the end of an iteration such that it's possible to revert if necessary without going through endless changes.
Assuming that your repository is divided into branches, trunk and tags, i'd suggest that you create a new tag.
Use the "Branch/Tag" command after commiting your work. It makes a copy that is called a tag and is stored (usually) in the "tags" folder.