As I don't see the harm Blizzard could have from this, it may as well be posted. If you download the beta (either from Blizzard or from a secondary source such as TPB or from fileshack), there are currently methods to watch replays even if you werent accepted into the beta. First, you have to install the game.

Here is a file (mirror) that does all of the above in one go except adding replays.

Seems like it actually works to just drag and drop the replays on the Starcraft2 exe-file, though you have to fix the cache as above for it to work. The cache in the above file may have two maps missing, you can get the full cache here. Which goes into the <device>:\Documents and Settings\<user>\Local Settings\Application Data\Blizzard Entertainment\\Cache folder.

Starcraft 2 is now playable!

Torrent. However, so far it is only a "sandbox" mode, meaning you cannot play against anyone, not even the AI but you can test all the units, buildings and so on.

If you find the sandbox mode to be too boring here is a custom map that at least gives you some enemies to kill (at the center).

AI Playable (though very stupid)

A map with 3 very poor AI players has finally been released. Use the sandbox mod above to load it.

Another update. A pack of 3 AI maps has been released, together with a "hard" AI mod. Though it is called hard it is quite an inaccurate name, but at least its an improvement, think of it as vs "easy".

There is actually a quite good AI up now (here). Try level 5, the protoss the AI is quite poor but if it plays zerg it is fairly strong.

For an even stronger AI. Try this chinese version.
Place in \StarCraft II Beta\Mods\Liberty.SC2Mod and rename it Base.SC2Data