If I understand your question, you probably want to change the productid #1 to a larger number, let's say productid #100
You can change the auto-increment values in your MySQL table with this command.
Code:
ALTER TABLE xcart_products AUTO_INCREMENT = '<YOUR_NUMBER>'
Replace <YOUR_NUMBER> with the actual integer value.
For example:
Code:
ALTER TABLE xcart_products AUTO_INCREMENT = '100'
Doing this on a live X-Cart installation is very risky, as many of the tables refer to the productid. So, my advice, only do this if this is a completely fresh install with no products yet.
MySQL docs:
http://dev.mysql.com/doc/refman/4.1/en/example-auto-increment.html
I hope this helps...