Most of the information out there about programming in S2AP is in blogs or references to really old OSGi tutorials. It took me long enough to configure some basic Eclipse project support that I figured it was worth writing down. All of the frameworks and tool sets are very flexible, which means you have more choices to deal with when setting up a project. Sometimes, being concrete helps... there may be a lot of options, but when it's time to do a project, you only care about one set of choices for those options. This guide is completely specific to using Eclipse to write bundle projects for SpringSource Application Platform.
If that's your specific set of needs, great! If not, that's OK too, because the beauty of the Web is that somebody else will have a tutorial on your exact combination, too.