Newbie FUD moment: live partitioning? Legacy Winblows apps and all...
If I understand your question... Boot Camp will allow you to partition your Mac OSX Hard Drive to create a Windows partition without disrupting your Mac's Boot drive. Then you install a modified version of WindowsXP SP2 or Vista (the software creates the modified boot CD/DVD for you from your original Windows disk) You can then run all your legacy Windows applications on the Windows partition.
You can also use that partition with Parallels to access your Windows apps in Coherence mode inside OSX.