Are you wanting just a two track mix down or are you wanting individual tracks from the board? And yes, it will be a little ackward not knowing what the desk is but the principals work on all desks.

What is a two track mixdown?

Are you wanting to record what is being mixed in the console that also goes to the "house sound system"? This would be a stereo ("2-track") recording...
The alternative is taking each source (voice or instruments) and recording each one to a seperate track - up to 24, maybe 32 tracks- on a "multi-track" recording. This would later be mixed down to a "2-track"....

As Moonbaby has said, the question really is whether you want to record the output of the mixing desk that goes to the auditorium speakers (this will be either mono or stereo depending on how it's mixed), or whether you want to record all the individual instrument and vocal tracks as they are before they are mixed plus any others so that you can do a separate mix for a CD after the event.

One major problem with recording the desk output to the speakers is that it will be (or should be) the balance of instruments and vocals that sounds right in the venue, which will not be the same balance or stereo spread required on a CD for replay at home. Because instruments such as bass guitars almost always have their own amplifiers on stage that produce the instrument sound in the venue, non of that instrument usually is taken directly into the mixing desk, although there is often plenty of uncontrolled "bleed" from the bass into other microphone channels that do go through the desk. Similar effects occur with a drum kit, and cymbals can easily wash over everything else if not carefully controlled.

Those of us on this forum who do quite a lot of live sound recording get used to putting up lots of extra microphones on guitar amps and on drum kits simply to capture the sound from these for recording purposes, knowing that these instruments are likely to be under-represented in any live mix. It's usual also to record a separate stereo pair of microphones for "audience reaction" to give more authenticity to a live recording. For some events, it's been only the vocal channels that I have taken from the stage microphones, with everything else separately miked for recording.

What mics would you use? Instrument Mics?

What are you attempting to do? This needs to be answered before we proceed.....:)

Well I am seeing what I need to do to make it work the best way it can.

We can't tell you what will work best without knowing what the end result is supposed to be. If it is just to record a live performance in a pub that is one path. If the goal is to be able to take the performance back home and actually mix the thing for CD or digital publication then a different route is required. You have not answered the question.

What is it you are trying to actually accomplish?

The Venue will be preformed live, with an audience.

It will be recorded as it happens, and then, after the venue, will be taken to production, where it will then be edited, and put onto a DVD.

In that case you need either a recorder that can handle all the channels on the board from direct outs, or you need a recorder that will do at least the stems + the main L-R mix. For this type of thing the two best options are an Alesis HD24XR or a JoeCo Black Box. Either of these can be chained in multiples if you have more than 24 channels being used. There are advantages to both but I think most touring rigs are moving to JoeCo for their backup to the DAW capture. I am agreed with the others that you should record the audio at 48k/24 bit.

http://www.joeco.co.uk/

I forgot to mention that there are several "standard" ways to grab these tracks. The first is to take a direct out off of every channel and run into the recorder. The mixing desk provides the mic preamps/DI's and any phantom power needed and the recording station gets what it gets.

The second is usually for folks that record for broadcast or are a recording crew separate from the front of house and is called taking a split. In that case mic splitters (hence the name) are used at the stage or stage box and one set goes to front of house and the other goes to the recording/broadcast booth. In this case you will need preamps for this recording station.