The nudge factor!
If you ever wanted to move an object just by a hair this is where nudging (as it's called) comes in handy, but first a quick run down of moving an object via the keyboard:
Simply select the object you want to nudge and using the arrow keys on your keboard your object will move in the following manner:
Left and right arrows moves an object along the x axis (horizontally)
Up and down arrows moves an object along the z axis (horizontally)
Page up and Page down moves an object along the y axis (vertically)
Now the nudge factor.........Shift+nudge direction your object will move 1/2 grid units
ALT+Shift+nudge direction your object will move 1/8 grid units
ALT+nudge direction your object will move 1/256 of a grid unit
1 grid unit is 20.48 (the diameter of a default sphere)
Maybe if anyone has a question this thread could be more helpful