European Sea and River Cruises

Information on Rhine River cruise/tour in Germany?

Does anyone have any information on touring the Rhine River and information on all the different castles and villages? Like, how long does it take to get from town to town? How much cruises or ferries are? Hotels? etc…
Thanks!

These sites offer a lot information on the cruises

http://www.koeln-duesseldorfer.de/englisch/index.html

and the Middle Rhine (points of interest, etc)

http://en.wikipedia.org/wiki/Rhine_Gorge

http://www.welterbe-mittelrheintal.de/index.php?id=318&L=3

Here’s a list of castles (sorry, only in German – try the links anyway):

http://de.wikipedia.org/wiki/Mittelrhein#Burgen.2C_Festungen_und_Schl.C3.B6sser

Viking River Cruises