Well, if you're a book kind of person, here are a few books that I've found very helpful, even when working solo:
I think I've reviewed them on my blog here, too. The problem you're facing isn't a "framework" problem, which is a design consideration, but an "organization" problem: How do you bring new developers onto your project, get them up to speed quickly, and get productive work out of them?
A couple of things that will be important steps towards that:
1) Have a version control system with code reviews. Early on, you may have to do most of the code reviews, but better team members should be able to step up to that responsibility.
2) Have integration testing. When checking code in, other people are, too. If someone makes a change that you were counting on working one way in your work, the two changes combined will fail. Having solid TDD practices will help with this.
3) Design! Having specifications for people to code against means their code can be tested and verified.
I know from experience that when I work solo on a project, I can be a lot sketchier with my designs, because I can work out the details as I code. When I had to design two interfaces to one area of functionality, and was only going to code one of the interfaces, things changed a LOT. I had to be certain the database backend was going to work for both, and that the way they laid down data in it was going to be consistent. A solid design and a couple meetings with the other developer were key to making that happen smoothly, which brings us to:
4) Meet regularly. It doesn't have to be for very long, but I've had weekly meetings, biweekly meetings, and daily meetings. With biweekly meetings, you completely lose track of what other people are doing. Major tasks get completed that weren't even on the radar two weeks ago. Weekly meetings are pretty decent, but can still leave you not sure what to do if you finish your work too quickly. Daily meetings let everybody quickly (how much is there to say since yesterday?) report on what was accomplished, what your goals are for the day, and what you're stuck on. It also lets you quickly assess who's progressing faster, and who needs more assistance: a major concern if you have a few 3 month interns.