Can Police Seize Cells?

From Fredericksburg.com:

If you are arrested, do the police have the right to look through your cellphone?

After all, they can already look through your purse, your wallet, your pockets-- or your car, if that's where you are when you're arrested.

Increasingly they're also looking through your phone, with the idea that your phone can hold evidence of a crime.

But whether they can legally do so--or should be able to legally do so--without a warrant is still a question up for debate.