Topic: Newbie partitioning XP HD for openSUSE 10.2 install


I am completly new to partitioning, Linux, GParted, but am determined to wean myself off Microsoft.   This is where I am:  60GB HD 100% formatted for OEM and XP on HP laptop.  About 40GB "free space" (not really because right now MS owns it).  Home burned openSUSE10.2 DVD.ISO.  C: imaged to USB HD (for backup).

As I understand it, I should burn the GParted CD, boot from it, and select my partition space.  This should liberate my "free space" to provide a home for Linux install while preserving my XP data, files etc. (how'm I doin' so far?).

My Questions:  How much space should I allocate to install, run, and grow my Linux OS?  What is dual booting, if I partition with GParted, will I have to boot into my Linux partition with the GParted CD, or how would this be done?  I hope to shrink my XP use down considerably, will I be able to run GParted again to reduce XP partition and increase resources for Linux?

Any help, direction, guidance, and encouragement is greatly appreciated.

Thank You,