Join Date: Mar 2010
Location: Whittier, CA
Bikes: Specialized Roubaix
Not to put you off but there are a bunch of identical threads all over this forum. I'll tell you to search for them, not as a put off, but because there is a lot of information available in them and you would benefit from it.
Item the second - I'd suggest a used mountain bike with NO suspension. Specialized hard rocks or whatever they were from the 90s fit the bill pretty well and they're pretty reasonably priced too.
Item the third - you're in great shape with so many co workers riding! I know you'll probably feel self conscious but make sure you take advantage of their info and good will - Many, many cyclists are happy to see new people pick up the sport and are only too happy to ride with somebody "slower" so don't be shy.
Numero quatro - your weight will not be "fixed" by cycling alone. You need to take a hard look at your eating habits.
Good luck with it all! I'm sure people will chime in with current advice for you too.
"No self-respecting man rides 70 miles and has salad at a pizza joint!" - PhotoJoe
"I like SoCal a lot better than New Jersey" - RubeRad