IL is the
USPS abbreviation for
Illinois.
Secondly, it is the incorrect way of spelling 'ill'. Now why would you go out of your way to misspell a word. Beats me.
'Il' is also 'he' in French. The plural form would be 'ils' (they), but you don't actually pronounce the 's', it's just there for your reading/writing pleasure, and of course grammatical purposes.
As far as conversation goes, many French speakers will suppress the 'l' sound. This is sort of like the slur in English when you say "y'know" where you suppress the 'ou' from 'you'. By suppressing the 'l' sound, only the 'i' remains and sometimes on ICQ, IRC or Email, it will be written as a 'y'.
For example:
Please do not confuse the
pronoun 'y' and this
slang notation form of 'il'/'ils'.
Thirdly, 'il' is also the Sino-Korean word (as opposed to Pure Korean) for 'one' and also 'day' (like Ilbon which is Japan in Korean).
N-Wing contributed to this writeup. Go give him a hug and kiss.