I want to give a player certain abilities when a specific item is in the hotbar but cannot figure out how to detect when an item is in the hotbar... Any suggestions?

A quick look at EntityPlayer and InventoryPlayer showed a few things. You could iterate over the mainInventory of the player which is in InventoryPlayer. Further you could only iterate over the items in mainInventory that correspond to hotbar slots and then getItem() on it and perform your checks.

 

Have a read:

http://jd.minecraftforge.net/net/minecraft/entity/player/EntityPlayer.html

http://jd.minecraftforge.net/net/minecraft/entity/player/InventoryPlayer.html

http://jd.minecraftforge.net/net/minecraft/item/ItemStack.html

 

FYI the hot bar comprises indices 0-8 of mainInventory.

Ok... I feel bad asking but what method should i use to fire the if statement?

Well. Use the field mainInventory in InventoryPlayer and iterate over only indexes 0 to 8 as super_aardvark has said. Upon each iteration you could check to see if that item is equal to the one you want.

You would probably need to use a tick handler to call the if statement every tick