First build your table as normal.
2nd build a second table with only 1 field in it, a number field. put in 1 record in this second table, the number 2499.
3rd build an append query off of the second tables, append to the 1st table autonumber field, run the query. this will put the number 2499 in the 1st table as the first record. Delete this record and you have now set the autonumber field to 2500.
Rob