Beginner help - typed dataset, sprocs, custom classes

Question

I am a new developer that started a project to build a rock group fansite using C# and ASP.net. I have a few questions on how to proceed with the project. Most of my database tables have been designed and looking to possibly follow Marco Belinaso's multi-tier design in his ASP.NET 2.0 book but I don't really see any information on ensuring accurate db transactions.

1) Should I use datasets or custom classes to contain data from the DAL?
2) Should I use stored procedures? If so, how do I ensure accurate database transactions that rollback in case there are problems with the transaction? I have limited experience with T-SQL.
3) How are multi-tier web applications usually developed (sprocs, ado.net, datasets, custom classes, etc)?

Thanks and I apologize for such a basic question.