Europe - European river cruises

I'm looking for information on European river cruises such as: lines to use,destinations,ships,. General question. Is everything provided such as beer and wines or do you have to set up a tab? I've never traveled on a cruise before. Thanks for any and all pointers.

There is a big market for river cruises and all kind of price and product categories, especially on rivers like the Rhine river.
I would firstly choose where you want to go, and then check what companies there are and compare their products: Languages spoken, exclusive or rather midrange etc. Usually full board is included and drinks go extra, but there are packages for alcoholic and non alcoholic drinks, so that for a fixed price you get unlimited drinks.
As I believe this market is especailly big in Germany, it can make sense to visit the website of huge online cruise travel agencies like e-hoi.de (or call them, I'm sure someone can also assist in English) and you will have databases on their websites (although in German) which will give you offers, routes and companies travelling. You can then even place your online booking.

The market is huge. It is like saying I want to go to the Caribbean on a cruise and what should I do.
There are many destinations and many companies.
Go to see Uniworld: http://www.uniworldcruiseline.com/?source=google ; it is a cruising company and download their European river cruise brochure. It is very long and detailed and I think it will give you a starting point.
Prices vary; once you know what you want, go to a local travel agent specializing in cruises and see if you can get a deal.

Try Scenic, Avalon, CroisiEurope, Viking and KD line for a start.

APT is another one as well....

Thanks for the input. I'll check out the suggestions.

There's also AMA Waterways. Travel + Leisure frequently publishes articles and poll results on river cruises.