Tar up key files by extension?

I would like to recursively troll through my OS X and or nix systems, find files of importance based on file extension, and put them in a compressed tar. The problem I am having is getting Tar to accept the standard input from the prior commands. Here is what I have so far using .doc just as an example: find / -type f -print | grep -iE '\.doc$' | tar -czvf test.tar.gz Something like that is my goal... Currently I am writing all results fromthe find/grep to a text file, then using the Include-files switch with Tar to tar them up via and && which just isn't as pleasing. Any ideas? HippieJoe PS. I tried using cpio with format tar then pushing it to gzip...i kept getting archive truncated errors.