The space shuttle Endeavour will be visible tonight from much of the United States, as the shuttle prepares for landing Tuesday afternoon at the Kennedy Space Center. This is a somewhat rare opportunity, in part because the shuttle spends most of its time in orbit docked to the Space Station, and in part because the orbital alignment needs to be right for bringing the shuttle overhead shortly after sunset or before sunrise. But these conditions are met tonight - the two are presently undocked, so they can be seen separately as bright stars moving across the night sky; and the orbital alignment is bringing these objects over the United States shortly after sunset.
To get the exact time (and place in the sky) for your location, try orbital predictions at Heavens Above. Choose your geographic location, then click on 10-day predictions for ISS (space station), and look for a pass on the evening of the 20th (tonight). Shuttle and station will follow the same track across the sky, probably within 1 minute of each other. Both objects will be similar in brightness to Jupiter or Venus - meaning they’ll be easily visible to the unaided eye, even from the middle of a big city. The visiblity will be short, however, usually about two minutes total duration. I don’t know for sure which is which - I’ve seen conflicting reports about which object is leading at the moment.
For some locations of likely reader interest: From South Bend, IN they will rise in the NW, be directly overhead at 9:30, set in the SE. From Nashville, TN they will rise in the NW, max elevation 33 degrees high in the NE sky above Cassiopeia at 8:30 pm, and go into the shadow in the east. Note these are really at the same time - these locations are in different time zones, but the shuttle is visible over much of the country as it goes over tonight.