Just got my 13"er too... since i'm in thailand.... i walked about 50yds from the apple store and bought a wd scorpio 500gB drive which the guys at the store imaged and installed for me - and i got the original 250gb as an emergency backup ;-) - the drive was 3150 baht, as opposed to an upgrade from apple cost of 5600 baht(!) and a wait of 2 to 3 weeks....
anyway... sorry, just gloating
to the 2nd question -
I now have windows xp installed also. I chose to install it first using bootcamp, this way it is always an option to boot fully into a 'native' (?) windows xp system. I chose to only use 32gB for the partition as it seems this allows FAT32 which then allows interchange between it and the Mac files system (a larger windows partition results in NTFS).
Then i've installed VMware (trial only so far) - installing the windows using bootcamp first is easy and also makes using it with VMware easy - you can then choose the bootcamp partition with windows on it, and away you go.
Very weird to see windows XP booting up from in a window within a MAC.... and even cooler when you click on the VMware Unity option and the windows ,errr, windows become just like any other window on your mac. My ewallet winXP program worked fine thru VMware and DVDcatalyst started up fine, too.
So - use bootcamp (it's free) and try out the VMware for a month to see how much you need it.
I'm impressed so far....
to the first question.... not sure best way as i'm new to this MAC malarkey - but some kind of clone software like Acronis, perhaps - or just save data to an external drive and reinstall MAC etc on the new 500gb (a hideous thought with a PC but seems like the Mac SL etc is a lot more pain free...)
Coops