shifters integrated into brake levers

It's actually the standard right on up to the high end bikes too! Nice how trickle down technology works, right?

So the shifter is actually a smaller lever that tucks in behind the brake lever. It moves side to side, whereas the brake lever gets pulled back when you want to stop. Most folks usually shift the smaller lever with a finger or two while never taking their hand off the handlebars. Nice, eh?

If you really want to understand it, just take a trip to your LBS and have one of the associates there show you how it works. It's probably the only REAL way you'll understand it. That's what it took for me years ago also. Very cool.

Good luck, and have fun!
-Tim

It's common on all road bikes.  In fact, other than tri bikes of course, I don't know if anyone makes independant shifter/brake setup.  They are all integrated...

It's pretty nifty actually.  You pull the entire lever towards you to brake (sqeeze), but the lever also rotates towards the front wheel to shift up.  There is a second smaller lever inside of the large lever that you also push towards the front wheel to shift down.

I happened to find this when searching just now and it explanes it well.

http://hollandsbicycles.com/page.cfm?pageID=508

It's a huge advantage over the older style of shifting on the down tube (or top tube on the lower end or very old bikes). Because you never have to move your hands off the hoods, you can shift up or down as often as the terrain dictates.  Of course, if you ride in the aero position, there is not any advantage. That's why tri bike have the shifter on the ends of the bars. 

The going to a shop is a great idea... but here's a pic.  Pulling the brake levers engadge the brakes... but that's a gimmee.  This is what most of the present high end setups resemble.  The brake lever and the little lever undernearth both pivot to the inside.  The shifter on the left(if these were on bars) would control the rear derailleur and the other would control your front derailleur.  The small inside lever on the rear control moves the rear gearing to a smaller gear, which gives you a bigger harder to pedal gear.  The bigger lever moves to a bigger gear on the rear making it easier to pedal.  

Again the left one that controls the front derailleur, the little lever shifts to your front small chain ring, which makes it easier to pedal.  The big main brake lever moves you back to your big chain ring, which is a "bigger" gear and harder to pedal.  

This isn't an all inclusive description, but my best feeble attempt to break down the shifting with these "new" integrated hoods.  In terms of shifters, I wouldn't go any lower than 105's.. that means Soras/Tiagras in the Shimano product lines.