Not sure if this has been posted.
Now I don't own an iPhone or want one for that matter but I just seen this ad on tv about it being a spirit level (not in those words!) on the apps page. Could be handy for aligning jammer heads if you already had an iPhone
Well heres the link:
A Level: Virtual Spirit Level for IPhone | Gadget Lab | Wired.com
[ame="http://www.youtube.com/watch?v=pQaDBkSAZX8"]YouTube - A Level[/ame]