Start with a rec ride with LBS. Look for a group that is welcoming to new riders and has a "no drop" ride policy, i.e., they won't ride off and leave you in the dust.

Ride with your normal bike for at least a month before you get a bike because at this stage you don't know what's best. Some options:

-- sat rec rides
-- midweek rec rides
-- finding out about local road training groups
-- if really want something different, go watch a local tri event

good luck & have fun