leopard runs great on my emac with lower specs than yours. my friend also runs leopard on an ibook w/ similar specs to your powerbook, i'll say go for it!
besides, if you really hate leopard you can always reinstall tiger
or even better, partition the drive in tiger w/ at least an 11gb partition for leopard, and install it on that partition to try it out
besides, if you really hate leopard you can always reinstall tiger
or even better, partition the drive in tiger w/ at least an 11gb partition for leopard, and install it on that partition to try it out