If you are planning on djing in a club then you wont actually need all the setup that a mobile dj has as the club will provide the sound system and lighting etc. sometimes you may be required to supply your own decks but this isnt a problem as it usualy just means simply plugging in the white and red wires into there amp (i forget there names now.. doh).
As for mixing, mobile djs usualy dont beatmatch like a club dj would and this is probably the best way for you to mix if you can beatmatch that style of music. you just cue the track in your headphones at a point where you think is best and then ... actually im talking crap lol... i dont know, as a mobile dj

... i could have a good stab at how its done but i might be completly wrong so i wont bother trying lol...
Usualy when i want to mix 2 tracks that are different speeds or styles like house into fast passed hard house its not a good idea to beat match so i wait for a break in the music where thers no beat and then bring in the second track with no bass and then when it gets upto the break at the end of a 4/8/16 bar section i bring in the bass and move the cross fader over to cut out the track still in its section with no beat... this usualy sounds decent if you get it right...
hope that makes sence anyway!
Good luck