It seems like people often want to grow VFTs in a terrarium, and that seems puzzling to me. They don't need it, and a terrarium introduces various problems such as stagnant water, stagnant unmoving air, concentration of fungal spores, overheating in sunlight, etc. At least that's the way it seems to me.
I guess I can understand the idea of wanting to grow plants in a lighted "display case" to highlight their special-ness--
--but it seems that Venus Flytraps really enjoy and benefit from fresh moving air, plenty of sun, plenty of open space to attract insects from, etc.
Here's an example (the photo below, with a link to the full-size version) of how I typically pot my own Venus Flytraps, in small colonies in insulated urethane foam pots (I really believe in insulating the roots of plants in containers--I believe it benefits the plants tremendously, and I can't understand why most seedling containers are a heat-absorbing black or dark green!). I know that everyone's techniques vary a lot. This is just one of the ones I use. I'm not trying to start a cultural war--just a discussion.
In addition to insulating the roots, I believe in giving them plenty of room to grow downward, and my VFTs roots almost always grow to the bottom of these pots and pots that have an inch or two more than this of depth.
Anyway, here's a photo of a pot of (very overcrowded, will be divided next Spring) Royal Red VFTs I snapped out on the back patio this fine Labor Day, 2006--
Link to larger version of above photo
Best wishes all--
Steve / xscd