I think its a bad name, but its an awesome program. I've just been trying it out and I'm quite impressed with its speed and simple but useful functionality.
To really try it out, I just wrote an XSL stylesheet to export my entire company journal to the simple text file format that ledger uses. It took a little tweaking, but so far so good.
Next up I'm going to try and import data which has been formatted as xml by ledger.
http://wiki.github.com/jwiegley/ledger
I also found this to be very very helpful:
http://furius.ca/beancount/examples/demo.ledger
UPDATE: Wow, ledger is awesome! I'm really enjoying working with it. I wish I had tried it earlier. Its very powerful, fast, and well thought out. There appear to be a lot of great people working on it too.