The Financial Times has a number of nice pieces about what you should look for in online MBA programs. You have to subscribe for a 15-day free trial to access the pages, but it is worth it and you don't have to purchase anything.

Here are a few highlights:

Fresh ways of learning ...
E-learning is in its infancy. Business schools are only now just beginning to realise its potential. But, while e-learning is the new kid on the block, distance learning is firmly rooted in the past.Web-based systems change the MBA landscape ...
As communication systems become cheaper and more accessible, new interactive technologies hold great potential in the design of distance learning courses.

Ways to reduce the sense of online isolation ...
Distance programmes must generate interaction for students in order for them to profit from courses and work effectively in virtual teams.