I'll borrow Oli's cut and paste job on this one for you
at the top of each post you will see 3 icons
the first will be orange or blue, this indicates whether the user is online or offline (orange for on, blue for off)
the 2nd one, which looks like a pair of scales is the rep icon. click this if you feel a post was particularly helpful (but only if you think it deserves it!)
the 3rd one, the warning triangle is to report a post, to mark the thread as solved just click the triangle and put "solved" into the reason for reporting.
I will mark this thread solved for you this time
edit: damn you Oli