rotation point

Support Modeling
1

how can i change the point of ratation
http://img90.imageshack.us/my.php?image=8t7ikjeg1.png

2

in the mesh edit buttons (F9) there are buttons to change the position of the object center (pivot point).
Centre: this button moves the object to be positioned around the object centre.
Centre New: this button moves the pivot point to the centre of the object.
Centre Cursor: this button moves the pivot point to the cursor.