Satellite dishes might be banned, but this doesn't mean that they aren't very widespread. This isn't the United States or Europe.
I believe there was an article in the NY Times about this exact issue. Everybody "middle-class" and up has a satellite dish. Every few months the government confiscates them, at which point everybody goes to the local black market dealer, buys a new one and puts it back up. Quite often the new one is their old one because usually the black market dealer is whoever is in charge of the local branch of the satellite dish confiscation agency.
Ah, reminds me of the bad old days in the Soviet Union.
we used to have Thuraya phones in Afghanistan for emergencies (http://answers.yahoo.com/question/index?qid=20090421134111AA...) - if they satellite you are trying to upload to DOESN'T point to the horizon, you could have your satellite pointing to the sky on the roof and people would be none the wiser.
But in a country where people live on roughly $2 a day (http://www.guardian.co.uk/world/2001/sep/25/afghanistan.terr...) I doubt many have $1,400 satellite phones that cost $6 a day to use.
Other methods are impossible...
Twitter is blocked through regular internet (see Michael C. McHugh comment here: http://www.politico.com/blogs/bensmith/0609/The_stakes_in_Ir... )
Cell phone towers are what's been cut so no SMS (http://www.google.com/hostednews/afp/article/ALeqM5jSPlmVgh-...)
Satellite dishes have been banned since '94 (http://ipsnews.net/news.asp?idnews=34407) so no highspeed internet that way.