tiny fish->tiny larvae->tiny mouths. What gogo7 already said, ciliates and other tiny microorganisms would be best.
If you can, I suggest getting a very tiny copepod species, like Parvocalanus. I recommend Parvo simply because it's a) a copepod, and b) easily supplied in the US via LiveAquaria. You could also try rotifers, but I don't really think the goby larvae will be large enough to eat the rotifers upon hatching. If you live near the ocean, you could also get live copepods by mesh straining.You could also consider using a large phytoplankton species as well...
As for actually raising them, gogo7 uses vases, kizanne uses cups, and Wittenrich uses black round tubs (BRTs). Whatever floats your boat, but remember that tiny container size leads to higher prey concentrations (a plus), but more easily changed water conditions (a negative). I suggest picking up a book on marine breeding to get a bit more education about raising marine fish larvae (Wittenrich's Complete Breeder's Guide is pretty good).
You might also want to check out MOFIB. I'm not sure, but there might be an account on raising goby larvae on there or something...
Congratulations on the eggs!! Good luck rearing them!