New switcher and have some questions

I am a new switcher and after wanting a MAC for quite a while I finally picked up one. My questions are: 1) Is there any way to set up the touchpad on my ibook G4 to have tap like in windows? I've scoured all of the setup screens and cannot find that option. MY next question is: 2) The computer is using OSX tiger 10.4 Since it is not technically my copy and no disks came with it I need to buy a copy of OSX and make a fresh install to wipe all the old data and users and have a legit copy licensed to me. Is there anywhere that you can recommend to buy a copy of Tiger cheap? I see snow leopard for about $120 on Amazon. The mac is an iBook G4 with 1 gig of ram, 60-gig hd 512k cache 1.42ghz processor. I don't know enough about macs or OSX yet to know if snow leopard would run correctly or if it would be like Vista and run, but not efficiently on an older comp. I know macs run differently than windows based and slower mac processors run faster than comparable windows PCs. Any help would be greatly appreciated. I really love the Mac and am SO glad to be done with Windows/Dell. I'm just sort of muddling my way through right now trying to pick up on short cuts and learn how everything works.

Firstly, welcome to the forum !

Question 1:
System Preferences - Keyboard & Mouse - Trackpad 'tab'
Look for 'clicking' - this lets you tap as a click etc.

Question 2:
You don't 'need' to get a new OS. Unless you really want to do a fresh install. You can get Leopard (not snow Leopard) if you want it should run fine on your iBook.

Amazon US have it for $110

It's 10.5.1 rather than 10.5.4 you'd get straight from Apple but it's $19 cheaper and the incremental 10.5.n updates are free and you can just get them over the internet once Leopard is installed.