You can install up to 2 GB memory in your PowerBook.
Tiger may be difficult to obtain. Apple no longer sells it, and aftermarket vendors charge a premium.
will updating to 10.4 tiger give me acces to the webpages of today or should i go newer?
"Webpages of today"... not all of them, absolutely not.
Many websites require newer browsers that unfortunately will not work on your G4.
If you try to keep up with all the gratuitous nonsense web page designers are so fond of implementing, you will be buying a new computer every year or two. Websites are often designed by programmers with $5000+ workstations, eager to show off their skills to clueless managers that are easily impressed with utterly meaningless animations that accomplish nothing other than to waste resources and bandwidth.
Get ClickToFlash. This will prevent Flash content from loading in Safari pages, other than what you want to load. Usually these are advertisements that to nothing but bog down your Mac.
Having considered all that, I would be reluctant to invest any more money in your PowerBook. It's getting to be nearly a decade old... an eternity in computer terms. You'll want a new Mac under the tree this year