Interleave merge pdf files

[Chirayu Krishnappa]

Hi,

I need to scan documents with pages having printed matter on both
sides. It is easiest to stack them in the autosheet feeder and let it
scan. I end up with one file (say A.pdf) containing the odd pages in
sequence. Similarly, I can end up with B.pdf containing the even pages.
I want to combine them into result.pdf which contains A.1, B.1, A.2,
B.2, A.3, B.3, ... (A.1 = page 1 of A.pdf).

Does someone know a simple way to achieve this? I noticed the other
thread on this newsgroup about merging lots of pdf files and
multivalent tools and pdftk were mentioned. However, I could not find a
way to do this using them. I am interested in another free tool or a <
25 lines python script (which may use any freeware library) to do the
same.

Thanks,
Chirayu.