XP/Ubuntu 7.1 dual-boot install questions

First off, I should say I'm a total Linux noob, but I would like to learn it and I've heard Ubuntu is a good place to start. I'm trying to install Ubuntu 7.1 on my new T61p laptop as a secondary OS. I've managed to find all sorts of documentation and help on creating dual-boot systems, but the only thing I'm not totally clear on is repartitioning my hard drive for the Ubuntu install.

I'm using the Ubuntu Live CD to make the installation, which includes a partitioning tool, but do I need to create a new disk partition in Windows before I install, or allow the Live CD to "resize" my partitions and install? Do I need to manually choose where Ubuntu installs, or is there no risk in obverwriting Windows with the Live CD partition tool? Also, how big should I make the partitions? I have a 160gb drive, with 60gb used and defragmented to be positioned at the beginning of the drive? Will both OSs be able to access files on either partition or do I need to creat a shared space? Obviously I'm a noob to this type of thing.

Thanks for the help!

 

1. resize from inside Vista
2. boot to ubuntu CD
3. when presented with the partition editor during install, choose "free space" or "open space" or whatever similar language. if you choose to install on "entire hard drive", it will wipe out the Vista install

 

This page does a good job of clearing up my concerns (in case anyone else is curious)

http://www.psychocats.net/ubuntu/partitioning