If the bike is your Cannondale it uses an English bottom bracket and specs for a triple usually call for a 118 mm width.
If the bikes use the same crank interface the existing bb may be fine if the width is correct and for this you will need a crank puller and if a different bb is needed you will need the right removal tools and installation tools.
Some bikes. Hell, they're all the same, ain't they?
I'm not being snarky by posting this instead of writing an explanation-recommendation thesis, but I'm dog tired and about to head to bed (working on three hours of sleep right now and it's already 9 PM ) --
5600 series cranks use Shimano's external BB cups; the spindle is already incorporated into the driveside crank arm. Any of the "road" BB cups (BB-4500/5600/5700/6600/6700, etc) with English threading should be fine.