Buy a Curled section of cork bark, sometimes sold as cork round or cork logs; smaller diameter logs work best.  Specialized reptile stores usually offer this form of cork bark.  Cork rounds also can be ordered from mail-order reptile businesses.  As an alternative, look in your yellow pages under cork.

Using a small handsaw, cut out a strip of cork the length of the log stopping a few inches from the "bottom" end, which will lie at ground level.  The top end will be leaning against the side of the vivarium or other structure.

Pack the bottom end of the cork log with dry green moss.

Fill the hollowed area you opened up with the saw with a mixture of 3 parts high-quality potting soil and 1 part small orchid (fir, not redwood) bark.  if you can't find orchid bark, add some sand to a standard potting soil mix to improve the drainage.

Add the plants.  Smaller bromeliads, waxy-leafed gesneriads (such as Aeschynanthus or Nematanthus), small Chinese evergreens, pothos, and a variety of other plants requiring shade-to bright-indirect light will fare well on the epiphyte log.  To plant the log, unpot the plants checking for ants, root meanlybugs, or other noxious pests.  If the base of the plant is free of pests, create a hollow in the soil mix in the log and drop the plant in; pack the soil so that the plant is firmly anchored.  Add a little more of the soil mix, if necessary.  You can also pack the top layer with moist green moss to prevent soil from washing off when you water the log.  If the base of an unpotted plant has pests, wash off all soil exposing the roots and pot in the plant's bare roots in the soil.  The only alternative is to treat the plant with an insecticide which will make it unusable for a long time.

Gently water or mist the soil medium around the plants until it is moist and place under the fluorescent lights.