If you are practicing on an electric guitar, you can effectivly play the insturment with no amp. The fingering isthe same, the strummng is the same, the sound is not.

Another option is to get an amp with a head phone jack and use headphones to shield those around you.

Or, get a pocket rocket amp, headphones, and cut the chord leading to an amp on the wall. Now you can play as loud as you want, anywhere you want, without disturbing anybody. You can then play anywhere with a very small amount of equipment required... Hell you don't even need to plug any thing into the wall, so you are free to play inside the house or outside.

Another idea is to get a Travler Guitar that even opens up hotel rooms, airports and any other crowded place for practice, any time. It is a minimal amount of equipment that can fit into a small, portable case. Stop watching the Departures/ Arrival displays clicking over, and over, and over... and practice your chords, and scales. As a bonus, the sound on these portable amps is pretty good through headphones. Once you put on the headphones, you are off into a world all your own. Flail away!!