What is a good scenery design program?

Hello all!It's time I started giving back to the hobby that has brought me so much enjoyment over the past five years! I am very interested in creating scenery for FS2002. I have never tried this before but have the motivation, time and patience to learn. First I have three questions:1. What programs are good to use to create scenery?2. How do I create (or obtain) individual objects to place in my scenery, for example a cell phone tower?3. What additional program (if any) is needed to get those objects into place? Thanks in advance!Regards,John