The regular ways of obtaining a Magento extension are:
- going to Magento Connect, logging in, copying the extension key, then entering it into Magento Connect Manager in the backend of a Magento site; or
- using pear on the command line
Both alternatives are relatively uncomfortable, and at least the first one does not allow to obtain the extension as a package file for download. But that might be necessary, in case you need to compare / dissect / evaluate extension code in development.
So I searched for a “direct download” alternative and found the freegento.com Download Magento Extension web service. Note that you still need to obtain the extension key from Magento Connect to be able to use this service.