Freeing up HD space on my MBP?

I want to free up some HD space on my older MBP, because I really would like to move my iTunes library back onto the computer from the external drive I've been keeping it on, but I can't seem to find enough free space on my 100 gig HDD.

The library is about 36 gig and I have about 17 gig space..

Much of the drive space is taken up by a Windows partition (32 gig).

1. Where do I look on Mac OSX to find files that are no longer needed?
2. How viable are the options for upgrading my HDD to a larger one? Would I be better served to wait and save my coin to buy a newer machine? That would take a while..

HDs are relatively cheap and a worthy investment. If you can afford one, can make a good backup and are comfortable installing a new HD, I would recommend it. If something goes wrong with the new HD, you still have your current one which you can put back in.

Truthfully, my recommendation would be to get rid of the Windows partition. At the very least, does it need to be 32GB? You could easily make it smaller. For instance, my Windows VM (Windows Server 2003), with a few things installed is 3.15GB. How much do you have installed on your Windows partition?

You could install something like Grand Perspective which will show you how files are distributed on your Mac and what kind of space they occupy. While this can be useful, if you don't know what a file is, don't delete it (even if it does take up a lot of space).

I need the windows to run a handful of softwares I cannot get on the Mac, which, incidentally, sucks. Currently, I am running about 2 gig shy of full on that partition too so I can't really reduce it.

I am comfortable enough with computer guts to manage an install, aybe thats my best path.

You could run Monolingual - its a free utility that will allow you remove any languages you don't need. This will typically free up about 2-3 gigs.
You can also use it to strip out the code from Universal Binaries that are not specific to your processor. In your case it would remove any Power PC specific code that you don't need on your Intel. (Caution advised)
Another way to recover disk space is to remove any Printer Drivers that you don't need. These take up another few gigs, and you can always download a driver again if you find you need it.

I'm with vansmith - even with deleting all the extra languages, code, etc. you'll only free up maybe 6-7GB of space.

You're also running your Windows partition dangerously tight. Doubt with 2 GB free that you could even run a defrag on that partition.

My personal advice is to maintain at least 20% free space on any system partition. Leopard will use up to 60 GB of virtual memory on a partition if you allow it the freedom to do so.

ok i do agree that a good solution is upgrading your hard drive. i upgraded my macbook to a 500GB for just under $100. here are two drives listed below. i do recommend using seagate but if you prefer another brand you can look and find the one you like. there is also other size upto 500GB and 5400RPM and 7200RPM just take a look for your self.

500GB - $89
Newegg.com - Seagate Momentus 5400.6 ST9500325AS 500GB 5400 RPM 8MB Cache 2.5" SATA 3.0Gb/s Internal Notebook Hard Drive - Laptop Hard Drives

320GB - $69
Newegg.com - Seagate Momentus 5400.6 ST9320325AS 320GB 5400 RPM 8MB Cache 2.5" SATA 3.0Gb/s Internal Notebook Hard Drive - Laptop Hard Drives