Well, I don't know of any consumer video cards that have THREE VGA ports on them, but I do know of a few that have three outputs, and then it's just up to you to either pick a card that has the adapters already, or buy the adapters.
This card has two DVIs and one HDMI that would work alright:
Newegg.com - JATON Video-PX638-DLP GeForce GT 220 1GB 128-bit DDR2 PCI Express 2.0 x16 HDCP Ready Low Profile Ready Video Card
Problem is, you'd have to find either an HDMI to VGA adapter, or, more conveniently, a DVI to VGA adapter (which is more common)
Is VGA the only input that your monitors can do?