WTB - 54 cm women's beginning road bike for triathalons

I baught my wife an entry level road bike, and put aero bars on it.
Spent $450 with the aero bars.....
It's defiantely an entry level and if she likes the sport will need a new bike in a yr or 2.
Had it since Dec and works great for a new Tri'er.

And for myself I got a used one on ebay and spent about $350.
But for the wife - new meant safety.....and less maint. issues.

What I got for her - http://www.windsorbicycles.com/willow.html
if you don't have a cycle spectrum in your city - you can get them online
online at - http://www.bikesdirect.com/products/windsor/willow2.htm( I have no expereince with them however)maybe you can find one on ebay too...
I paid a little less at my LBS ($399 at cycle spectrum)
The equipment on that bike is what I would call - very basic. And other bike shops will be-rate the components....and lack of carbon fork...but unless you are doing iron mans...that won't really matter to you...and you can always upgrade things like that later....or buy a whole new Tri-specific bike later.

BIke fit is very important......more important than the bike itself.
If you buy online I would recommend paying a local bike shop for a fitting before you buy online. But if you are into reading you can figure out your general size online.

good luck.

Sounds like you are tall enough that you could find a men's bike to fit you...I wouldn't limit yourself to just a woman's bike...might be a prettier color though

Don't get hung up on men's bikes -vs- women's bikes. As long as the frame fits you, you can pretty much take any frame, change the bars/stem/seat-post positioning, and it will fit you fine.