parse/slice/...

[rcmn]

I'm not sure how to call it sorry for the subject description.
   Here what i'm trying to accomplish.
the script i'm working on, take a submitted list (for line in file)
and generate thread for it. unfortunately winxp has a limit of 500
thread . So I have to parse/slice the file by chunk of 500 and loop
until the list is done.
I though i would of done it in no time but i can't get started for
some reason.
And i can't find a good way to do it efficiently . Does anyone have
something similar to this.

thank you