question about offset in general

i'm pretty new to wheels and offset stuff so I was wondering what does it mean to have an offset of a + number or a minus number??

A negative number means the offset is behind the center of the wheel, positive means in front of the well.

like this 

                                     Center of the wheel

                                                    l
Negative offset                            l                 Positive offset
(Side where it bolts to the hub)                    (Face; the side you see)

It messed up my little diagram but basically look at the wheel where you would see the tire tread dead on like youre bout to go ran over. If the offset is positive it means that the face is further on the left side of wheel from the center. If its negative it means that it's closer to the inside of the wheel from the center, on the side where it bolts to the hub.

Make sense?

[IMG]http://www.raceandroad.com/images/ns-offsetexplained.jpg[/IMG]

ahhh ic thanks man.

Here is another place you can look. It has pictures too

[url]http://www.discounttire.com/dtcs/infoWheelOffsets.dos[/url]