a key question is are their foreign keys tied to the current identitiy?

if there are, it makes it a lot harder, since you'd have to update those child foreign keys to a new number if you changed one key to a new value.

if there is not, you could simply create a new table(ie tablenameNEW with the layout;then insert into that table(INSERT INTO tablenameNEW(columnList) SELECT (columnlist from tablename), rename the original table (sp_rename t'ablename','tablename_bak')and maintain it as a backup, and rename the "new" table to the original tablename.(sp_rename 'tablenameNEW','tablename') you'd then have 250M records with room for 2,2 billion more.

-edit- just realized that everyone suggesting to use the GUI to drop the column and re-add it is the faster, easier way to do the same thing i suggestioed....i need more coffee today, since i said exactly that on a similar post yesterday.