You need to do:

export DISPLAY=:0.0
aticonfig --pplib-cmd "set fanspeed 0 100"

export DISPLAY=:0.1
aticonfig --pplib-cmd "set fanspeed 0 100"

and so on, for all your adapters.

edit: missed the question about changing clocks. To over/underclock, use:
aticonfig --od-setclocks=950,300 --adapter=0

That would set your first video card (adapter=0) to gpu clock 950 and memory clock 300.