VIP

VIP is a multiplayer gametype in the Halo 3 Beta and Halo 3, confirmed by bungie podcast, similar to Assassination mode in Gears of War.

There are four standard VIP modes: VIP, One Sided VIP, Escort, and Influential VIP

All of these modes are just variations of the same set of options. So, for customization purposes, it does not matter which you select to use as a base.

VIP

In standard VIP each team is assigned a VIP and players score points by killing the opposing team's VIP.

One Sided VIP

In this game mode, only one team has a VIP.

Escort

This game mode is similar to One Sided VIP in that only one team has a VIP. However, in Escort there is an added objective: the VIP can score points by arriving at checkpoints. In some maps, a common strategy is to use vehicles to drive the VIP to the destination(s) and by default the VEHICLE USE is set to PASSENGER ONLY for the VIP so that his or her team is responsible for driving. This was made famous by Rocket Race. Where there is four teams of two and the VIP must ride shotgun to get to the objective to score.

Influential VIP

The key aspect of this mode is that special traits can be assigned to players who are in a specified proximity to their VIP (e.g. extra shields). The default setting is that both teams have such a VIP, though this can be changed.

Notes:
If you play One Sided VIP or Escort or otherwise have the SINGLE VIP option set to ENABLED, then there will only be one elephant on Sandtrap (the one labeled "Behemoth" on the side closest to the downed Albatross). This is useful information for Forgers, as if you build on "Leviathan" and SINGLE VIP is ENABLED, everything you place there will instead start at the top center area of the map.