As Roger says, use scp.

It might still be useful to know how to tar into a pipe, though. To do that, specify "-" as the destination file, thus:

tar cf - my/directory/

and at the other end:

tar xf -

For example, the following is the equivalent of cp -rp dir1/* dir2:

tar -C dir1 cf - . | tar -C dir2 xf -