First the info:

-it's rap/hip hop
-i heard it around 1998 but definitely before 2000
-lyric wise all i remember is an altered voice (like t-pain's) saying 'nobody', 'dbg? or dpg?', and something like 'slurpin or surfin'
-asking from the US

I heard it in a friend's car and at the time he was a big fan of Sugar Free and Lil' Rob. It had an old school beat, much like More Bounce to the Ounce. I tried asking him but he had no idea what I was talking about. Please Help! =]

Well the voice saying dbg or dpg reminds me of Disturbing tha Peace (DTP) which is Ludacris's group. But since you are very sure you heard it before 2000 then I don't think this is possible.

The slurpin or surfin part kind of reminds me of the chorus to Three 6 Mafia's Sippin on Syrup, but that came out in 2000.

California Love doesn't really meet any of your descriptions and that seems like something you would know right away.

I have no idea who Sugar Free or Lil' Rob are and that makes it even harder. I think your friend is your best bet but post some more clues!

oh i'm sorry it's Suga Free if that helps any