that from your cell service? Or is it coming from the person you call? I've been getting it a lot lately.

Yes.
I get that a lot with cingular around 3 o' clock.

I worked at a telephone company for 7 years and now with a cell company in customer service. The thing about you situation is it could be either you or the person you are trying to contact. Their must be something not working correctly (trust me they know about it) It's rare usualy this only happens in high volume situations , like a big storm comming and people are calling all their relatives or like during 9/11 tonz of people were using the phones bogging up the networks.