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Check out this Excel spreadsheet based imbuing calculator by Zolaf of UOForums.com:

http://chat.stratics.com/zolaf/Zolafs_Imbuing_Calculator_Current.xls

You can read her original post here:

http://www.uoforums.com/rp-alliance-message-board/93933-imbuing-calculator.html#post605560