When you create a field, set it's type as lookup wizard. You will then be asked to pick the linked table, and lookup details.
It will create a field of the type you define as the bound column of the lookup table, but will display the value from the data column you select, rather than the bound column. ie, if you pick a number column to be the bound column, the data type in your main table will be a number. If you pick a text field as the display field, your table field will show text (although it is actually storing the ID number.)
The field properties in the table will show as "combobox" in the lookup tab. Change combobox to text box, and you get rid if the lookup. The REAL value in the TABLE stays the same as it was before you changed the lookup.