1. Download the conversion script and rename it to .php rather than .php.txt
2. Take a backup of your b2evolution database, just in case (if you’re on Windows, SQLyog is a good, free program for working with MySQL databases).
3. Download the latest version of WordPress and upload it to your site using your FTP program. You don’t have to delete the b2evolution files yet. You will have to overwrite the existing index.php file with the one from WordPress though.
4. Make sure you know the connection details for you b2evolution database - if you’re not sure, you can find the information in the _config.php file of your b2evolution install (in the conf folder).
5. Fire up your browser and go to [www.yousite.com]/wp-admin/install.php. Run through the normal WordPress install procedure, but make sure you enter the same database details you use for b2evolution (including the database name). This will create the required WordPress tables alongside your exisiting b2evolution tables in the one database.
6. Upload import-b2evolution-wp2.php to your site, in the wp-admin folder, and fire it up in your browser: [www.yoursite.com]/wp-admin/import-b2evolution-wp2.php. Follow the instructions, making sure to enter the same database details from the last step. You should hopefully see a success message, in which case your b2evolution posts, comments, links, users etc. will have been copied into the WordPress tables.
7. Remember to delete the install.php and import-b2evolution-wp2.php files in the wp-admin folder. Now go to your blog’s home page, and you should see the default WordPress install, populated with your posts from b2evolution.
8. If this has worked, you can safely delete your b2evolution files (be careful not to delete any files you might want to keep, such as those in your media or skins folders) and delete any database tables prefixed with evo_ (but don’t delete any prefixed with wp_).
9. Permalinks. Obviously you don’t want to break the links to your old posts, which were probably in the format /year/month/day/post_title in b2evolution. If you turn on date and name based permalinks in WordPress, you’ll find spaces replaced with dashes rather than underscores in links for new posts. However, your old posts will still work even though they use underscores. Sweet.
Hope that helps.
Please tell me how it goes!