Here are 2 very good Player-Made Imbuement Guides.
The first one, by Dadi (Proudcdn), is a useful guide on what it is, and a little on how it works.
https://www.lotro.com/forums/showthread.php?566679-Dadi-s-Guide-to-Imbuement&highlight=imbuement+guides
The second one, by PKCrichton, is a detailed guide on how it works.
https://www.lotro.com/forums/showthread.php?567833-Imbued-Legendary-Items-Guide&highlight=imbuement+guides
NOTE: The highlighted words in these guides is a result of my search.
The third link, by Frelorn, is a list of the Legacy changes.
https://www.lotro.com/forums/showthread.php?568084-Update-16-Legacy-Changes-and-Updates-Full-List
{UPDATE, 8/18/15:
Here are 2 more references, these by Kaleigh Starshine. The first is on Legendary Weapons. The second is on Imbuing them.
https://thecottageofpenandplay.wordpress.com/2015/07/03/legendary-items-tips-tricks-and-a-guide-to-the-grind/
https://thecottageofpenandplay.wordpress.com/2015/07/06/imbued-legendary-items-tips-tricks-and-a-guide-to-the-grind/ }
NOTE: It has been Recommended that one should experiment on an unimportant 3rd Ager first, in order to learn the new process of Imbuement. After one is familiar with the process, then, and only then, apply it to the weapon of choice. Mind you, it will either take grinding, or much mithril to imbue ONE weapon on ONE alt. There was a backlash against the cost/grind.