To install the laser tank patch just type laser
at the prompt in your command and conquer directory.

In itself, the laser tank is no big deal, but if you use a program
like ccedit to give it a laser cannon (of course jacking up the price
as well), it can be quite an interesting weapon.  I leave the laser
tank's actual attributes up to you (as is, it will just be a really
cool looking humvee).

Thanks to Vladan Bato for mmlite and ccnames.