Well this post has been a long time coming. Around 3 months ago I presented to Drupalcambs a presentation about extending the migrate module to enable you to map and import data using the fantastic migrate module. I say fantastic as the migrate module lets you do some awesome stuff when migrating.
Previously it had been hard to properly insert nodes (with files/taxonomies), taxonomy terms and users, however, utilising the new fields that Drupal 7 gives us has made it so much easier.
Below is the slides from the presentation that I delivered and a quick tar/zip of the files to make a small migrate module yourself if you have a quick look at the files you will see they should be fairly easy to adopt to migrate almost any textual content into Drupal. I you are looking to do some more complex migrations then have a look at the migrate_example module within the Migrate module which houses a plethora of different migration examples for all kinds of purposed, or even get features running and whack on the migrate_example_baseball which puts in content types etc.