tebfunk

Yes! It's actually the best way to go. You'll basically drive West towards Dubai and then turn South East. You'll want a map, but you basically take the 89 to 88 to 611 (signs will say to Dubai Marina or Abu Dhabi) and the the 66 to Al-Ain. It's basically a triangle, but the Emirati roads are better, so it doesn't take as long as it looks like it should. 3 hours tops.

A note on highways - locals will not refer to the road names or numbers, they will give you landmarks. The signage is *very* good however, so if you have a map or know where you need to go it is easy to get around.

Also - when you cross back in to Oman from Al-Ain you want to use the southernmost border crossing. The signs will direct you to the crossing in the North, near the Al-Hilli archeological park, but that will put you on the wrong road if you want to see the desert towns in Oman (and you do!). Even if you don't stay the night you'll want to drive through town to the Hilton (well signed). The Hilton is at the intersection of Khaled bin Sultan St and Zayed bin Sultan St, and it's the latter that you'll want to take south to the border (about 15 minutes outside of town).

Edited to add: Mr. tebfunk just chimed in to be aware that very few of the gas stations on the peninsula take credit cards - something that surprised us. If you have other questions about the area feel free to ask - we just got back from living in Abu Dhabi, and spent a great deal of time exploring the region.