is it possible to take a large number of files & tar/gzip and stream them on-the-fly?

Question

I have a large number of files which I need to backup, problem is there isn't enough disk space to create a tar file of them and then upload it offsite. Is there a way of using python, php or perl to tar up a set of files and upload them on-the-fly without making a tar file on disk? They are also way too large to store in memory.