If you have a significant number of articles, that's a real problem. Copying and pasting all these meta tags can take hours, and because Joomla 1.5's database structure is so different from that of Joomla 2.5 it’s impossible to do make the move directly on the database.
So we’ve built you a new migration tool. iJoomla Migrate SEO allows you to export the meta tags from an old site and import the meta tags to the new site. It's very simple.
But... iJoomla Migrate SEO ONLY works if you use the JUpgrade or SP Upgrade migration extensions to create your new site. Other tools may change your article item IDs.