You will need a NLE that supports multiple Video Overlays and moving paths to split the Video. You can look at ULead Medistudio Pro, Adobe Premiere, Vegas, Avid etc.
Try this post http://www.videoforums.co.uk/ftopic548.html and check out those software packages that offer free trials.
COMPAQ something or other with 500Gb Boot Disk, 1Tb external Firewire Disk, 4Gb Memory and a super duper sound card, 19" TFT Monitor etc etc etc
Sony TRV33e : Sony TRV310e : Canon XM2
Sony Vegas Studio editions to v11
Remember, there is always more to learn than there is to teach.