The difficult thing that appears with moving the products using the migrate moduel appears to be the inability to put multiple tables into one table. To counteract this I ended up migrating all ot the Oscommerce product data into one database table and then sending the content over with the migrate module. The code ended up something like this although this is obviously editable dependant on what data you have in Oscommerce/want in Drupal:

Product aggregator to take products from Oscommerce and dump into a mysql file for insertion to Drupal Database.

$oscommerce_database = 'oscommerce';
mysql_connect('localhost', 'root', 'password') or die('Cannot connect to MySql');
mysql_select_db($oscommerce_database) or die('Cannot connect to database');

$sql = 'select * from products';
$query = mysql_query($sql);

echo "CREATE TABLE IF NOT EXISTS `products` (
    `products_id` int(12) NOT NULL,
    `products_model` varchar(25) default NULL,
    `products_price` decimal(15,4) NOT NULL default '0.0000',
    `products_weight` decimal(5,2) NOT NULL default '0.00',
    `products_length` decimal(6,2) NOT NULL default '12.00',
    `products_width` decimal(6,2) NOT NULL default '12.00',
    `products_height` decimal(6,2) NOT NULL default '12.00',
    `products_name` varchar(64) NOT NULL,
    `products_tab` varchar(64) NOT NULL,
    `products_description` text,
    `short_desc` text,
PRIMARY KEY (`products_id`)

echo ''."INSERT INTO `products` (products_id, `products_model`, `products_price`, `products_weight`, `products_length`, `products_width`, `products_height`, `products_name`, `products_description`, `short_desc`) VALUES ".'';

while($result = mysql_fetch_assoc($query)){
    $sql_desc = 'select * from products_description where products_id = '.$result['products_id'];
    $product_query = mysql_query($sql_desc);
    $product_desc = mysql_fetch_assoc($product_query);
    $product_id = $result['products_id'];
    $product_model = $result['products_model'];
    $product_price = $result['products_price'];
    $product_weight = $result['products_weight'];
    $product_length = $result['products_length'];
    $product_width = $result['products_width'];
    $product_height = $result['products_height'];
    $product_name = $product_desc['products_name'];
    $product_description = $product_desc['products_description'];
    $product_description = mysql_real_escape_string($product_description);
    $product_description = htmlentities($product_description);
    $product_st_desc = $product_desc['short_desc'];
    $product_st_desc = mysql_real_escape_string($product_st_desc);
    $product_st_desc = htmlentities($product_st_desc);
    echo "($product_id, '$product_model', $product_price, $product_weight, $product_length, $product_width, $product_height, '$product_name', '$product_description', '$product_st_desc'),";