I just chug them and follow up with a swig or two of water. The general idea's to not "just" eat the gels and drink nothing, so long as you drink "some" water as well, it should be good.
Anyone tried Endurosnack? Recommended by the Czech olympic team, looks like tubes of toothpaste. They've got caffeine, creatine & loads of other stuff as well as sugar, seem to perk me up fairly well (although at the end of a run I get a strange desire to jump in a tank and drive towards Moscow...

)
I'm thinking I'll start with the gels after about an hour in my marathon, maybe 8miles, 13.1, 18 & 22 something like that