As a backyard astronomer I've been relying on a mixture of free and inexpensive resources to guide my viewing. Here's what I use most nights:
- Stellarium: Very pretty open source planetarium software. I use this to get a very realistic view of what my sky might be like on a given night.
- Equinox 6: Not too expensive, and plenty powerful for my needs. It also allows me to establish the specifics of my telescope and lenses, giving me a realistic expectation of what I might see through the scope. I use this to plan my viewing (and will use it for webcam captures as well once I have that up and running). Well worth $50.
- Andrew Johnson's Mag 7 Star Atlas (color): Another example of what's wonderful about the Web. This is a full set of color start charts down to magnitude seven, free. I have them printed and in a three-ring binder (in plastic sheaths). Just great.
- A printout of the Messier object list from Wikipedia.
Regarding websites, there are several I visit regularly: