Slightly off-topic (or not) but I thought I'd cross-post it here anyway.
This suggestion from BoingBoing
via DougJ/Balloon Juice
actually sounds useful:
4. Help cover the bloggers: change your twitter settings so that your location is TEHRAN and your time zone is GMT +3.30. Security forces are hunting for bloggers using location and timezone searches. If we all become 'Iranians' it becomes much harder to find them.
To do this, just log in to your Twitter account, click the "Settings" link at the top of the page, make the two changes, and click the "Save" button at the bottom.
As you might have guessed from the "4," there are other suggestions at the links. Some require tech savvy, others are just good common sense.
[Added] Also via DougJ: Interesting bit of statistical analysis suggesting fraudulence
in the vote counting on the WaPo. Also, of course, there's plenty to consider on 538