The Microsoft Partner Program offers resources and benefits to support ISVs throughout the development lifecycle. In addition to development resources, ISVs also can take advantage of marketing and sales opportunities.

By helping ISVs successfully build solutions on the Microsoft platform, Microsoft benefits too.

You can get a great overview of the benefits for each partner level from http://msdn.microsoft.com/isv/partnering/default.aspx.

Basically, the Partner Program is tiered and you can engage at the level that is most beneficial and appropriate for your company.

I hope this helps answer your general question.

-brenda (ISV Buddy Team)