I see references to the Obama campaign requesting, then calling cell phone numbers. Some of the above comments are inaccurate.
The law, at 47 USC 227, provides that it is illegal to call a cell phone using automated dialing equipment for ANY REASON unless EXPRESS permission has been previously provided or there is an emergency. It does not matter if it is non-commercial. It does not matter if it is for charity. If your cell phone is dialed by an automated dialer without your express permission and it is not an emergency, you can sue the caller for $500-$1500 for each violation of the law or regulations.
For the purposes of this discussion, cell phones should not be called unless candidates have express permission to call citizen’s cell phones. Unless of course you want pay people like me $1500 when they sue you.
Also regulated are prerecorded message calls to residential lines (and cell phones, which by law are treated as residential lines) which must identify the caller and provide a telephone number at which the caller can be reached. The Utah Attorney general made calls in which a telephone number was not provided during the last election. Hmm.
The point is to be careful with technology solutions to get the message out. Even if legal, candidates may alienate voters with calls for which permission has not been granted.
The statute and the regulations made under that statute are easy to comply with. No point making stupid mistakes.
See:
47 USC 227:
http://www.law.cornell.edu/uscode/47/227.html
47 CFR 64.1200
http://frwebgate.access.gpo.gov/cgi-bin/get-cfr.cgi?TITLE=47&PART=64&SECTION=1200&YEAR=2001&TYPE=TEXT
