Some of my early brews did this.
What did you prime with?
How long has it been in bottles out of the fridge?
and not that important...but what kind of beer?
You could have a problem with over priming, or just letting it sit and carbonate too long.
Also, I have no idea if this is true, its just from personal experience. I seem to have more foam problems when I prime with priming sugar. I've had much more predictable carbonation priming with DME. YMMV