That Duron will work just fine. I gave my father a old IBM R30 laptop i had with 384mb sdram, a PIII 1Ghz Mobile, a Ati Rage 8mb, and hes delighted.
Surfing, Office tasks (Open Office) a bit of MSN. He uses Firefox 3 and the machine is on Windows XP.
Just playing Java games seems like pulling teeth. Starcraft plays really nice. Still good for some lan action with my brothers