Of most interest is that the press release describes not just a license to practice the inventions in IV's patent portfolio (i.e., not get sued for infringement by IV), but also the ability to "borrow" the patents for use against competitors:

Becoming an IV licensee provides access to additional products and services to address both short-term and long-term IP-related matters. As an IV customer, RIM can now complement its own strong patent portfolio with access to IV’s portfolio and can leverage IV’s portfolio in its future licensing negotiations.

Source: Intellectual Ventures