We have a great video that answers this question and many others about the LEED Credential Maintenance Progrm (CMP), which is worth viewing.
To answer your question, "legacy" LEED APs, those without a specialty, can earn IDc2 for their LEED 2009 projects without restrictions, as the project administrator or another integral team member. The only current LEED rating system that requires a specialty is LEED for Homes.
For future LEED rating systems (LEED 2012), it's possible this could change, so keep an eye on things. You may want to opt in before the window closes in 2011.