I've always thought it a shame that all those tweets we produce every day eventually end up disappearing into the ether, never to be read again. Then I stumbled across Twournal, a new service that allows you to immortalize your Twitter musings forever by turning your tweets into a book.

You can use Twournal to create, buy and sell Twitter books printed from your tweets. You simply sign up with your Twitter account and the service will generate and mail to you a free eBook containing a date-ordered record of your posts through the ages. It even includes color pictures taken from Twitpic, Yfrong, TweetPhoto, and the like.

If you want to purchase a hard-copy, printed and bound book of your tweets, prices will vary from $15 for a standard book of less than 800 entries, to $135 for a tome fashioned from between 2,400 to 3,200 posts with full color pictures. Check here for the full price list.

At the moment, Twournal is still in invite-only private beta. Luckily for you, we've teamed up with Twournal to offer 100 free invites. Head to the Twournal home page and click 'Create Twournal' then choose the third option: 'Create Twournal when you get your invite code'. Enter the code 'onsoftware' and you're ready to start making your own personal Twitter journal!