To get here you can either drive from Sanaa via Marib or Al Mukalla as I did or if you are pressed for time you can fly Yemenia into Sayun and it is a 15 min or so drive from the airport.
I would suggest driving in and flying out if time is critical. Shibam sits in the middle of Wadi Hadramawt which is basically a huge canyon full of small villages...Not the Grand Canyon..but close in my book and more fun to see.
Most tours are organised to drive from Marib across the empty quarter to Hadramaut. At the time of my visit the FCO wre not allowing Brits to visit Marib so we flew from Sana'a to Seiyun, the main town of Hadramaut and drove to Shibam from there.
The view from the plane over the Hadramaut landscape is stunning and it is worth having
your camera ready if you arrive by plane.
Form Seiyun, you can take shared taxi for YR100 (30 mins) to Shibam. The taxi will wait for 5 pax beofre it starts off. From shibam, the atxi with the same fare for return. But the later you come back, i.e. the darker the sky is, the most difficult for you to get shared taxi and you may end up chartting a taxi for YR500-1,000 (May 2008). So do take note.
See pic for taxi condition.
Collective taxis to Shibam leave Sayun from a stand just past the new market, near the main taxi-rank. Getting a shared taxi can take some determination, as you will probable be canvassed heavily by the taxi drivers. Should you succeed, it'll cost around 200YR for a place: a taxi to yourself will be about 1000, depending on your bargaining skills.
And possibly the weather. It had rained heavily the night before my first visit: wadis were turning into rivers and we got three quarters of the way to Shibam before encountering a stream the driver was not prepared to ford. So we headed back nearly as far as Sayun and took an alternative road. So I had to pay more.....
Unless you already have your own jeep+driver (like most tourists do) the best way to move around the cities (Shibam-Say'un-Tarim) in Wadi Hadramawt) is shared or contract taxis.
There were many yellow coloured old aged taxis at the main entrance to Shibam village. Drivers speak minimal or no english. But for a good price you can hire a taxi for sightseeing all these cities in one day.
The good news is that NO permits were requested to travel around these cities plus NO police check points... Very relaxed!!