Hi,
put LinkButton instead of hyperlink and then on link button's click event put following code...
isql = "select max(yourfield) from your_table";
cmd = new SqlCommand(isql, con);
int pval = Convert.ToInt32(cmd.ExecuteScalar());
pval=pval+1;
isql="insert into your_table (yourfield) values (" + pval + ")";
cmd.ExecuteNonQuery();
Hope this helps...
Enjoy Coding...