small string split prob

[ian]

hi im having trouble splitting a string any help would be great!!
The RCPTTO contains a line read from a socket.
when i try to split an e-mail address into the box and domain sub parts i
get a type error on index!?

#split e-mail address
index = RCPTTO.find("@")
box = RCPTTO[0,index]
domain = RCPTTO[index + 1,RCPTTO.len()]

print box
print domain