Richard has put together a list of O/R Mappers and Code Generators for .NET Development. Here is the list:
Codus (Free)
Codesmith (Free/$)
CSLA (Rocky Lhotka) (Free)
DataObjects.NET ($$)
Deklarit ($$)
EntityBroker (Free/$$)
Genome (Free/$$)
Gentle.NET (Free)
Ironspeed ($$)
LLBLGen Pro ($)
Modularis ($$$)
Neo - .NET Entity Objects (Free)
NHibernate (Free)
NPersist (Free)
NOrca (Free)
ObjectMapper ($)
Objectz.NET ($)
OPF.NET ($$)
ORM.NET (Free)
RapTier (Free/$$)
Sooda (Free)
Visual Developer ($$/$$$)
WilsonORMapper ($)
XPO - Express Persistent Objects ($$)
I have used a number of these products and I can personally vouch for the quality of three of the products - Codesmith, Deklarit and LLBLGen Pro. I use these products a lot and have found them to be of very good quality, and the technical support for Deklarit and LLBLGen Pro are excellent.