You can take photos inside?

[DrunkenGiraffe]

So my mum has volunteered me to take photos tonight at her golf club's big formal dinner for the year. But... I haven't even used my camera inside...or at night before. I bought my first dslr a few months ago, but haven't had that much time to use it yet. I don't really have a choice about doing this so I need some quick advice.
I have a Nikon D5000 with 18-50 VR and 55-200 VR kit lens. I only have the pop up flash on my camera. I asked what kind of photos they want, and its stuff like people accepting prizes, couples/group shots and general shots of people having a good time. In same places it might be fairly well lit but others not.
So I don't really have a choice but to use my flash? What kind of setting would you use then? I'm assuming I will have to use the biggest aperture I have but I can't really use a lower shutter than 1/50 or so. But if people are dancing/moving then I can't really have a slow shutter speed without blur...
Also about how far will the flash go? A few metres in front of me?
Any advice would be awesome

 

[reznap]

I'd open up the lens... maybe use ISO 400, 800 if you have to. Set your shutter speed to maybe 1/60... see what the exposure looks like without the flash. Go for a "little bit dark" look. Now, use your popup flash to get a shot of someone, in front of whatever backrground - people eating whatever... Set your flash exposure compensation so they are a little brighter than the background.. so they stand out. You should get some decent results like that, in theory.

EDIT:

I'm a bit embarrassed to share this photo... lol. BUT it's an example of what you might want to be shooting for.
Using my Rebel T2i, Tamron 17-50 f/2.8

Exif:
Aperture = ƒ/3.2
Exposure Time = 1/100 second ===> 0.01 second
ISO Speed Ratings = 400
Flash = Flash fired, compulsory flash mode

Make sure you shoot in RAW as well...
Good luck!