I love my mac ibook g4, however i have restrictions when I want to player a mp4 or any other application of that nature. I have mac os x version 10.3.9; can anyone help me?
No, there's not a free (legal) download for 10.4.x
And I'm sure you wouldn't trust a big download like that to be safe, or complete. You will need to find (purchase) a copy of 10.4.x somewhere. Check on eBay for a commercial set (Black DVD with a nice big "X" across the disk would be good to look for. Steer away from grey-colored disks, which will be only for the Mac model that they originally shipped with.)
If you have an iBook G4, it's very likely that its 1 + Ghz, so you might as well buy leopard and upgrade your iBook all together, I think that the iBook G4's came with 256 soldered into place, the g3's have 128, so you'll either have to get another 256 stick, 512, or you can go ahead and put a 1 gig in and max it out.