Not necessarily all Japanese smileys are in parentheses. Usage of parentheses around the smilies seems to be on a fairly random basis, and is partly personal choice. ^_~ is another common way to wink. (example: "Heh-heh, you like tentacles, don't you? ^_~ If ya know what I mean...")

@_@ deserves a slightly better explanation than above. It indicates surprise and bewilderment, and is rather cartoony: the "@" symbols for the eyes are rather like in cartoons, where a characters eyes will turn into spirals to show how confused they are. (example: "Yeeks! @___@ How did I fail this test? I thought I did good...")

~_~ is another somewhat common smiley you may encounter. It's used for either annoyance or tiredness, depending on the situation. (examples: "~_~ It's late, I need to go to sleep, but I'm reading a fanfic so I can't yet..." or "~_~ What are you talking about, you idiot?")

=^.^= is seen occasionally. It's supposed to look like a cat, I think. It can indicate the user's feeling a bit mischevious and clever. (example: "Nya! =^.^= Isn't that cute?")

-^___^- is a face that's happy, but blushing slightly. It doesn't always have that many underscores, it can vary. It's sometimes seen if the person's embarassed over having drawn/written something, or if they've just gotten a very nice compliment. It's often followed by a sweatdrop (";") but not always. (example: "-^___^-; I can't believe I just drew yaoi..." "-^___^- What, you think it's good? Ahaha... Thank you...")

>_< is like your eyes scrunched shut and eyebrows lowered--it's an angry or annoyed face. (example: ">_< Grr! You idiot! Shut up!")

O_o is a nice common smiley, too. A variation is "o_o" or "O_O" It indicates varying levels of surprise/confusion, like you have your eyes wide open. Using capital O's (O_O) indicates you're really shocked by something. "o_o" is less so, and "O_o" is slightly more confused--one eye's really wide, and the other isn't quite so huge. It's a little like raising an eyebrow, I suppose, but not quite. This one's commonly followed by a sweatdrop, too.(example: "o_o What the heck are you talking about?" "O_O Yeeks! Put your clothes back on!" "O_o;;; What on earth are you doing? Get away from me...")