Yup - they're the same exercise basically. The only trick is to watch your back position when you're doing the 2nd link you posted. Exrx is a great site but their form isn't always the best. Basically do what that guy is doing, but don't move your back/shoulder around so much. He drops the shoulder and thats exactly what you don't want to do - keep it stable. The whole idea is to keep your upper body stable while your arms and back muscles do the work.
You can also do the same thing if you have a high enough bench by lying stomach down on the bench, starting out with the dumbells a bit above head level, and then pulling them up towards you arcing in towards your chest. You stop right about when your hands are besides your watermellons. That would also help keep your chest isolated.
A good complimentary exercise to that one is this:
http://exrx.net/WeightExercises/Deltoid ... Press.html - which you can do with dumbbels sitting upright. Start with them straight out from your shoulders and press them up and together until they're right over your head. Same thing minus the cables, plus you'll get the stabilizing muscle bonus.
A great site on female weight training is
http://www.stumptuous.com. It's down at the moment for some reason, but lots of great info there!
Edited to add: don't neglect your ab workouts too - quite a lot of lower back strength actually comes from your abs.
