I have picked up a second pistol in Crysis 1 on Xbox 360 and now I am stuck with Dual-Wielding pistols and I just want to use one. I googled how to drop a gun and it told me to use the "J" key...but as everyone is aware the 360 gamepad does not have a "J" key. I hope this will be fixed. Seems like a really weird miss on the developers part.

From a quick Google search:
http://strategywiki.org/wiki/Crysis/Controls#Weapons

I think the web page was referring to playing Crysis on PC with an Xbox controller, but it says you can't drop weapons
Try looking in the controls page of the game

Yeah I'm having same problem.

try going to weapon customization and pressing random non=used keys there maybe.

There is no way to drop weapons that I can find, tried all kind of button combos.