Whenever people are paying me money to do an assignment, I feel that it is incumbent upon me to make sure that I can complete the job, even if one camera goes down. The same for the lenses and flash units.

For lenses, I would recommend fast aperture lenses because they will allow you to shoot slower ISOs, higher shutter speeds and shoot available light later in the day.

With regards to posing...keep it simple. When I am photographing a couple I ask them to find a comfortable spot (usually in the shade) and snuggle together...people will naturally find a position that is comfortable to them. You might have to tweak that a bit, but usually people will place themselves in a comfortable position. Watch the position of hands around the waist, position of the bouquet (not too high)...try to get people to relax and it will show in the pics...be really critical of everything that is in the viewfinder...don't wait to crop it later...try to get everything (exposure, composition, and moment) correct the first time in the camera.

If you don't mind the shameless plug, I've got a wedding class here at betterphoto.com.

I hope this helps and don't hesitate to post any follow up questions.

Good luck and have fun!

Best,