API:FollowUnit

FollowUnit(unitid) Causes the player to follow the unit

unitid
string - "target","focus1","party1","raid1","mouseover","pet" -cannot follow yourself "player" -you can follow your pet but you will wonder around aimless. blind leading blind lol.

example
/script FollowUnit("party1");SendChatMessage("I am following the leader","Party");

Note There is a range limit to this function and seems to be same as tab targeting range.