Not sure if 2007 is the same as 2003 but in 2003 if you want to show a drop down box with say the values of months, Jan, Feb, Mar, etc then you need those values in a table that the combo box will look up. You use a combo box from the form tool box. That will bring up a wizard asking what you want to do with the combo box. Simply point it to the tables with the values you want to look up.
If you are looking to do this in a table (not on a form) I would counsel highly against it. See here for more about lookups at table level: http://www.mvps.org/access/lookupfields.htm
You can do it on a form and just using the control wizard when adding a combo box to the form will help you get it set up.
Just thought I would add to Bobs point in advising against having the look-ups directly in the table. I did that when I started my database and then a while down the line realised it was making everything so much harder as the values the table displays are not the same as the values it is actully storing.
If you scroll towards the end of this link Pat has a very neat way of keeping all the values used for the drop down lists together.