love2respectseo - 3:03 am on Apr 22, 2010 (gmt 0)
Google particularly limits 50000 urls or the size of file upto 10 GB. So, for so robust sites like directory, you have to segregate your urls category wise and then you have to make different XML sitemaps for different category and submit it in google webmaster tool.
Then make a final XML sitemap where you have to locate the other sitemap's address and it would also have to submit on google webmaster tool. This is the process i think for the best in dexing of your huge urls. If there are other processes, let me know.