It's much easier to spot and identify a satellite if you know when and where to look. On the Internet, SatPasses
provides online predictions for passes of several bright satellites over cities in North America. In addition,
software for home computers is widely available to produce satellite traffic reports for any location and date.
A selection of available software may be found at the following sites.
Satellite Observing Resources
Mike Macants' Page
CelesTrak
Among my personal freeware favorites is Quicksat. This is a simple no-frills satellite prediction program. There are no fancy graphics here; the output is in tabular form. You can print out a hard-copy traffic report and head out for an evening's viewing. However, I have found it more convenient to load Quicksat's output onto my Palm Pilot. The Pilot's lit display and ability to set alarms make it a useful addition for the satellite watcher. If you are both a satellite observer and a Pilot user (and everyone should be), feel free to use this PERL program I wrote to format Quicksat output for the Pilot.
All satellite prediction programs depend on having a current list of orbital elements for the satellites they are tracking. Satellites' orbits change with time. They may be intentionally maneuvered into new positions, or their orbits may change as they experience drag from the tenuous upper atmosphere. Also, the population of satellites changes with new satellites being launched and old satellites burning up. Fortunately, updated sets of orbital elements are freely available on the web. Note that sets provided by governmental organizations may exclude elements for classified satellites. More complete sets may found on Ian Burrell's Satellite Observing Resources, Mike Macants' Page or on T.S. Kelso's CelesTrak.