i have searched the web and only come out the ones need to pay...
is there any free software just to the simple job of split the video by time(like a 100min video split into 100 1 minute videos)
You can always use nandub, it have option to split file by size (chose File->Save segmented avi, unfortunetly minimal size is 50MB :/), or you can select a part of movie and save it (select Video->Direct stream copy,Audio->Direct stream copy and then Video->Select range, and File->save as avi... ).
I know this isn't free, but if you have windows xp it comes with windows movie maker for free, and the program is relatively simple to learn or use.
If you have and apple computer, I really can't help you there...
For video edition, there isn't much choice :
For Windows™ : VirtualDub
For GNU/Linux : Avidemux
For splitting the video into smaller pieces, I'm goign to have to say your best bet is VirtualDub. It's pretty impressive program for being free.
NanDub might essentially be the same but with a minor differences and whatnot. I've only used VirtualDub.