Look up… no a bit more.. not that far! Look what the lovely people at WordPress have set up for us – Domain Mapping! The last piece is in place for my blog. I’m getting good traffic, I’m enjoying writing and exploring new ideas and I now have my domain in place! Don’t worry, none of you have to do anything. WordPress has made it all so simple. all of my links have been updated across and everything is working seamlessly. I exported my blog to back it up anyway (WP again, all comments, posts and categories backed up with the click of a button) but it all went according to plan.
It’s here: you can now use your own custom domain with your WordPress.com blog. For example, if your blog was currently at example.wordpress.com you could buy example.com from us and we would automatically move your blog over and redirect all your links and readers to the new domain.
Domain Registration and Mapping « WordPress.com:
Since moving to WP I think my blog has benefitted outrageously. They roll out new and exciting features all the time and it is easy to work with – not only that but it is very personal with a fantastic community feel. I heart WordPress.
Jennie's Palette 
The only thing I found I had to change with http://beatsentropy.com was RSS feeds.