the web abounds with plans for fish tank stands. If you can't find one here, try reefcentral.com and search. I've seen a couple over there. While you do need to respect the weight of the aqaurium, typical 2x4 material will easily support it. Where people go wrong is not including some means of diagonal bracing or using fasteners that aren't up to snuff. (Diagonal bracing may or may not mean a true diagonal support, more often its multiple fastening points). Just follow one of the posted plans if you aren't sure.

