Upgrading from 10.4.11 (Tiger)? Mac Power PC?

Hey guys...
I'm using a Power PC Mac running 10.4.11 still, and I'm very confused about upgrading (if its even possible) to Leopard or Snow Leopard, or anything better than Tiger for that matter. I've been using Tiger since it came out and I love it, although I want to upgrade all my apps (garageband, iLife, iDvD, iMovie) so I figured the best way would be to just upgrade my whole system if it is possible. I do not have an Intel-Based Mac, so I'm not sure what I can do. Please help?

Thanks!

Well a standard upgrade of Leopard OS X.5 does require a minimum of 867MHz processor although there are some work-arounds to enable install on slower models. Snow Leopard OS X.6 is for Intel machines only so Leopard is as high as you will be able to go.

Does help if you provide machine specs to be able to answer your question better. If this machine is the G5 iMac in your avatar, then Leopard will install just fine. Suggest 2GB memory.