Go to a drugstore and look for Porcelana cream. It's made exactly for this. I'm pretty sure they still make it.

Drugstore.com has it, just so you can see what I'm talking about:

http://www.drugstore.com/qxp85875_333181_sespider/porcelana/fade_dark_spots_nighttime_treatment.htm

It's probably a sun damage spot if it's on your face. Just a guess.

I have been using Obagi products for 2 monthes... it is quite expensive but all of my sun spots are GONE!!!

I've noticed a definite change in my skin since coming back from Hawai'i in April.  I'd been so good staying out of the sun for years and then whammo...

*sigh*

true. Most of the premature aging we deal with is from sun exposure, and most of that is the day to day exposure (i.e., in car, walking to and from car, etc)
Even when you're not getting a sunburn, the other type of ray is still at work damaging your cells and wreaking havoc on your skin's defenses. The only way to protect from boty UVA and UVB is to daily use something with either avobenzone (aka parsol), mexoryl (new one) or if you don't like chemical sunscreens, one with titanium dioxide or zinc oxide.
Especially if you use any AHA (glycolic acid) or even retinol, or salycilic product, be even more sure you use spf every day. Otherwise, you're just throwing money down the drain w/ your aha product!
sorry to repeat myself- I am a broken record, I know. But for anyone who hasn't heard me "go on and on" about sunscreen yet,  I'm just an advocate for proper sunscreens---sooo many sunscreens out there for the face actually don't contain one of those key ingredients. And if you don't see one, then they only thing it will do is help you not get a sunburn, but it won't stop sun damage (i.e, wrinkles, spots, etc).

More importantly, if you use an AHA, it makes your skin more sensitive to the sun and thus likely to burn faster than usual.

I do not. I am just interested and read a lot---and I'm a skin care and cosmetics junkie---I think I could write a book of my escapadaes.  lol.
exactly---all of the aha/bha products, retinols, etc make skin more sun sensitive, but that is not a problem as long as you use spf everyday---there isn't really another way to get rid of the spots unless you use laser treatments.
But, if you use aha or bha combined w/ a hydroquinone product, you should see results. Again---use spf everyday or you'll just be nullifying your efforts.

I wish you luck!!
My sister is actually having laser treatments on a sever brown spot she has, she used to be a sun worshiper, but she works in an office where they offer the procedure, so that's really the only reason she is doing it---as it makes it very affordable for her.