Guideline Properties Dialog Box
This dialog box allows you to enter the exact position for the guideline. Type a value (for example "2cm" or "3in") and click OK. If you are creating a new guideline, clicking Cancel will stop a new guideline being created.
Tip
 The units used for the guideline 
 position are the Page Units set for the document, see Changing 
 the page units. Note however that the units used on the rulers (and 
 grid) are set using the Grid 
 and Ruler Options.
 The units used for the guideline 
 position are the Page Units set for the document, see Changing 
 the page units. Note however that the units used on the rulers (and 
 grid) are set using the Grid 
 and Ruler Options.