Avi Sagiv, a colleague at Microsoft, just sent me this list of Microsoft programs and resources that every software developer should know about:
Empower. If you are building a product, you get free (or very close to free) access to almost every Microsoft tool and product.
InnovateOn. Technical and business resources for products like Windows Vista, SQL Server, Dynamics, Office Live, Windows Live, ...
nxt. Help migrating applications to the Microsoft platform.
ISV Royalty Program. Embed Microsoft products in your solution.
Service Provider Licensing Agreement. Pay as you go licensing for SaaS solutions.
Channel Builder to create partnerships within a worldwide partner community
The Microsoft ISV Site. Resources, resources, resources