Note that this is likely dangerous and you shouldn't do it
It currently take 9+ hours to completely reprocess the testnet blockchain when downloading it from scratch via Geth. This has almost nothing to do with download speeds - instead, it's the time it takes to import each block and validate them that's the culprit. And the chain is big, very big - because we encouraged the Olympic phase users to push as many transactions as possible on a network where gas is in effect, free.
For this same reason, if you try to geth export, then geth import the testnet chain, you'll find it doesn't save time either.
So, is there a solution when you're in a rush? Well, kind of. If you simply overwrite your chain directory with one from a client that is already up to date, geth seems quite content to accept it and simply pick up from where the other client left off.
Now, please note this is really a non-solution: the chain I'm making available here as a download could have been messed with, its data modified to the uploader's advantage (me). I can only give you the SHA1 for the file and hope a middleman won't rewrite my post and link to a corrupt file, for example.
I had a brief chat with Jeffrey about this and we agreed that if we were to one day distribute the chain this way, it would likely be over Swarm (our decentralized storage layer, currently in development), and several failsafes would be in place to help prevent forgeries.
However, I understand that the recent stress test has made it difficult to reimport the more recent blocks, and until a fix is out, well, overwriting the chain will save some of you several hours. It's a also a nice little test of what might become 'a thing' if it gets automated (with the SHA1 posted on as many of our 'out of band' channels as possible).
So, without further ado, here's a link to thetestnet chain as of yesterday, July 10th 2015. It was extracted from ~/.ethereum on OSX, but should be compatible wiht any Geth RC1+ install.