Hi koger,
I would recommend you NHibernate in Action book, it's really a good book if you want to build applications using NHibernate and you want to take full advantage of it.
Regarding database design - in my opinion if database design is good for other application building styles it should do good also for ORM. Joe Celko has quite good hints for database design. Here is one of his articles:
http://www.intelligententerprise.com/001205/celko1_1.jhtml , which point out some convention, design mistakes, and good practices.
For Winforms I would also recommend you .NET remoting if you need fast data transfer and if you are building application for LAN networks. MSDN has a lot of help files, articles, and examples how to do it (e.g.
http://msdn2.microsoft.com/en-us/library/kwdt6w2k(VS.80).aspx).
Regarding tools you can try our product
NConstruct Lite, which was released today. It creates source code for entities and NHibernate hbm files, using your database metadata. I already posted a brief presentation post about it today (
http://forum.hibernate.org/viewtopic.php?t=984039). It is a free tool so you have nothing to lose. :-)
If you need additional help on any topic, please let me know.