SIMM Inventory software

Does someone know of a software inventory utility that will tell me how many and what size SIMMS are installed on my windows XP machines? I have over 30 Dell Optiplex GX 270’s that have either 256 or 512 installed in some randon chip set configuration.

I want to upgrade all the PCs to a gig for some new software, but dread going around and physically opening up each machine to do inventory.