Any simple way to maximize memory available on 32-bit Win-7 (under the 4 gb limit that is) ?

[Nomen]

I've upped the ram in my Dell 6420 from 4 to 16 gb (I might set up a 64-bit Win 7 on it some day) but for now I'm running Win-7 ultimate 32-bit and system properties is reporting 2.92 gb usable memory.  I know it can't use all 4 gb but I've read where it should (?) be able to use a little more - maybe up to 3.5 gb ?  What can I do to maximize that, bring it close to that 3.5 gb number ?