Currently in Abu Dhabi the only one available is the iBT option. For a list the dates which you can take the test in your city please refer to the website below and scroll down until you get to your city.

http://www.ets.org/Media/Tests/TOEFL/tclists/BOTH_u.html

There are three ways in which you can register to take this test: online, phone and by mail. For more information on each visit the website below.

http://www.ets.org/bin/getprogram.cgi?urlSource=toefl&newRegURL=%2Fportal%2Fsite%2Fets%2Fmenuitem.1488512ecfd5b8849a77b13bc3921509%2F%3Fvgnextoid%3Df968af5e44df4010VgnVCM10000022f95190RCRD%26vgnextchannel%3D6cd6197a484f4010VgnVCM10000022f95190RCRD%23online&test=TOEFL&greClosed=new&greClosedCountry=China&browserType=Firefox&toeflType=iBT&redirect=&t_country1=group_UnitedArabEmirates&newParm=2006-05-20&TestCenter=All+IBT+Locations+-+%28iBT%29&date_selected_old=

Also note that there is a iBT TOEFL test fee of $170 (USD).

If you require and further questions or queries then refer to the link in the source, you will find all the answers you are looking for there.

Good luck.