Importing Movable Type post tags

Hi there. I am new to WP and am trying to write a utility that converts MovableType tags to WP tags.

I think the logic goes something like this. Let me know if I am wrong:

– Join the wp_terms and wp_term_taxonomy table on term_id. Must have taxonomy = ‘post_tag’. Search where name is the MT tag name.
– If it doesn’t exist, add it to the wp_terms table. Not sure how to filter out special characters for the slug column. I assume blanks are turned into underscores. Increment the count in the wp_term_taxonomy table for the term.
– If it does exist, increment the count in the wp_term_taxonomy table.

Is there a routine that creates slugs I can steal?

Are there other tables I need to be mindful of, such as wp_term_relationships or wp_usermeta? If so what needs to go in these tables