The Navy is getting the EA-18. Supposedly, and I'm not holding my breath, even though they are starting to atleast train FRS instructors, that the Navy will be getting their first Growlers in 2007 with an operational squadron by 2009. I've only heard this through heresay, but out in Pax River, they're hanging the pods on F models to get the software up and working so that the transition can be as quick as possible.
The Marines on the other hand will be getting the Prowlers the Navy no longer wants. That seems to be how it always works. The same thing happened the Hornet. Unfortunately, the Legacy Hornets are really showing their age. The Marines have been getting the trapped-out Navy Hornets, and their pretty beat. There's even rumors floating around that the Marine D-models might be heading to the boat in place of the C's.
Alot of this is rumor and speculation, but the next 10 years are going to be a really interesting transition period for both services.