Click to view attachmentWindows XP skinned for Tiger, with all freeware. I haven't done this in ages, so most of my good pictures are missing.
Tiger .msstyle VS
Samurize
RocketDock
nExplorer 1.9
MacSearch
Trillian 3 iChat skin
Safari close-minimize-maximize mod
iTunes multi-plugin
If you want it to seriously look like OS X, but don't mind dropping some cash, I'd recommed Object Desktop ($50). It provides you with several tools (WindowBlinds, ObjectBar, WindowFX, ObjectDock, and more) that let you radically change the appearance of Windows.
I haven't used Windows in months, so I'm sorry I can't be of more help, but as to your questions.
First off, you're going to need Lucida Grande. This is Mac OS X's main font; it's been plastered all over the internet.
Next you'll need a proper
Mac OS X Leopard .msstyle.
Leftsider is a neat little tweak that moves the close-minimize-maximize to the left.
nExplorer is a very convincing Finder clone featuring column view.
Oh, and Mac OS X icon sets are everywhere on the internet.