First wedding on 12 April

Just wanting some advice.

Im going to a wedding in almost 2 weeks time and it looks like im going to be the main photographer (unpaid) as the couple really dont have the money for a professional. There will be others with cameras but i get the feeling they are relying on me to get most of the pics.

Just looking for some advice:
1) Are there any "must take" photo's? Im not sure if i will get a chance to have a decent conversation with the B&G before the day.
2) Should i try to take control to get the shots i want? Or would you suggest trying to get someone in the party to help?
3) Do you think my gear list will be up to the task? I dont have backup for anything so im hoping for no breakdowns.

Any comments would be helpful.

1 ) Yes, plenty of them, really I think the goal is take photos of any details that may be important.. First Kiss, Rings, First Dance, Cake cutting, etc.. There are lists all over the interweb, use Google, it is your friiiiiiiiiend.
2) Well, it depends on the style. Personally I would go for a natural photojournalism style myself, I shot my first wedding Sunday and I kept saying.."Pretend I'm not here!" hehe. As far as if you are doing formals, then yes you should take control there. I am really not sure what shots you're talking about here.
3) Well I am not a lens expert but the 18-50 f/2.8 should do nicely I would think..

Thou the number one thing is.. do you have some sort of back up camera? Even a p&s digital camera would be better than nothing. Also you may want to see if you can find a second shooter to shoot with you? Even someone else who is portfolio building.. That's what I did Sunday and even thou she's fairly new she got some great shots.

Thanks for the advice Auroraskye.

Any more tips folks?

I'm in a very similar situation to you.. I got a wedding coming up this summer.

Yesterday I bought a Sigma 24-60 f2.8 so that I'm covered for indoor church lighting with no flash, because my 17-85 will not be up to the task. I'm hoping it will work well and you 18-50 should too. The rest of my gear list is similar to yours.

I'm thinking of picking up a XTi at Best Buy and keeping it in the trunk of my car just incase something goes wrong with mine. If all is good, return it to the store unopened.

I'd use the Sigma 18-50 as the main lens with a flash for fill in when you can.
If there is enough light, then I'd use the 70-300 but you may find this lens too slow to AF and also too slow in Max. aperture.

As for must have shots? Getting ready shots with the bride. Groomsmen shots, bride with bridemaids shots, the ring shot, the whole family line up shot come to mind for me.

If you are of the perfectionist type, you may find that this is a lot of work to get and process as well.
I'd also take a lot of memory and an extra battery for the body and the flash.

Ive got 8 Gb over 4 cards so hopefully I should be ok for about 800 shots. The camera is gripped with 2 batterires + one spare so i should be ok for that and with 3 sets of rechargables (high capacity) i think the flash should be ok as well (hopefully).

Think i will try for the 4 shots you mentioned Tee +the cake and first dance if i can as the very minimum. Hopefully some B&G and ceremony shots if possible.

I'd check out various wedding shots to get ideas on composition and stuff as well.
Good luck.