Unique text for each page to be shown in sidebar

Hello,
I am facing an issue which is far more complicated that I expected. I have a 3 rows layout, so that the left sidebar is navigation, the middle part is actually body and I need the right part to show some additional text for each page.
For instance,
http://www.leif.ru/newleif/ – index page with company description on the right
http://www.leif.ru/newleif/?page_id=15 – some other page with quote of the U.S. president on the right
So each page has a unique text that is to be insterted to the right sidebar.
I had to do it using meta tags which is I am sure not the best choice.
So I a looking for a sidebar/widget/hack to fix this problem, I am sure I’m not the only one who faced it.

Thank you

P.S. I also tried to use php in the page, but looks like the code in he body is processed later, so
– in page body <?php $somestring=”String”; ?>
– in sidebar.php <?php echo $somestring; ?>
did NOT work