sure it is, it's just data. I did the same thing as I have an existing site too with 10,000 items in it. I created a C# win app that referenced subsonic and I set up my app.config to work with subsonic and pointed to my new and old databases. Then I read in a record from my old database, created a new Product record, and inserted. You'll discover that you also need to insert data into the foreign key tables (manufacturer, category, sku, image, etc).
If you add your tables to a new sql database diagram (right inside SSMS), it will graphically show you the table relationships. It helped me to see how all the tables related to each other.
Good luck,
Scott