We're running our game via IRC, so I thought I'd put this up for people who intend to use irc to save you guys the trouble.
on *:TEXT:!roll*:#:{
  set %dice 4
  set %sides 6
  set %i 0
  set %total 0
  while (%i < %dice) {
    inc %i 1
    %roll = $rand(1,%sides)
    if %roll = 1 { set %roll - }
    if %roll = 2 { set %roll - }
    if %roll = - { dec %total }
    if %roll = 3 { set %roll o }
    if %roll = 4 { set %roll o }
    if %roll = 5 { set %roll + }
    if %roll = 6 { set %roll + }
    if %roll = + { inc %total }
    set %roll $+ %i %roll
  }
  msg $channel 4Roll: %roll1 %roll2 %roll3 %roll4 4Total: %total
}