Apple just published on its website a page dedicated to the iBook Logic Board Repair Extension Program.
This program targets a number of iBooks manufactured between may 2002 and april 2003 (serial number UV220XXXXXX to UV318XXXXXX), showing the following symptoms:
* Scrambled or distorted video
* Appearance of unexpected lines on the screen
* Intermittent video image
* Video freeze
* Computer starts up to blank screen
If you are unlucky enough to have an iBook with this problem, contact Applecare or bring it to an authorized Apple retailer and they'll get it repaired for free, within 3 years of the date of purchase.
Get more details on Apple's website :
http://www.apple.com/support/ibook/faq/
[UPDATE] one of our French reader tells us he had the problem with a UV319XXXXXX series iBook and was extremely pleased with Apple's tech support:
I own an iBook 900 with a UV319XXXXXX serial number. Apple replaced its logic board a week ago for those same symptoms (garbled display). It seems the yhave a bit underestimated the extent of the series concerned with the problem. Nonetheless, it took only 3 days between my dropping the iBook by my Apple retailer and getting it back in shape (Bravo!). Yoann Blériot