A standard glass aquarium usually works fine. There are a wide range of aquariums availible, they don't just come in your average rectangle anymore, so you can usually find something that will work for your situation. If not, you can always have a company like www.glasscages.com build something for you or even build one yourself.
Some species of dart frogs are very bold and are almost always visible in the terrarium while others are shy and only come out when food is availible. I would suggest a larger species for a display terrarium. You might want to look into D. tinctorius, azureus, galactonotus or P. terribilis or bicolor because they all grow to a large size and have a reputation for being bold. The humidity in the terrarium will also have a large effect on how shy the frogs are. If you can keep the humidity up around 90-100% even the shyest species will pop out a few times a day.
There are a few books about dart frogs and within those there are chapters about creating a terrarium but, as far as I know, there isn't a book dedicated only to building a display terrarium. Most of the dart frog books are either out-dated or just not thorough enough. The best, or at least most up-to-date, information about these little gems is right here on the internet. Here are some websites to help you out:
http://www.doylesdartden.com/
http://www.blackjungle.com/basics.htm
http://www.tropical-experience.nl/
http://home.earthlink.net/%7Ekenuy/vivarpage.htm
http://www.rygepetersen.dk/terrarium.htm
http://www.frognet.org/gallery/
http://www.thebdg.org/
http://www.amphibiancare.com/frogs/caresheets/poisondartfrog.html
http://www.amphibiancare.com/frogs/articles/tropicalterrarium.html
Good luck,
-----
Devin
devin@amphibiancare.com
www.amphibiancare.com
0.0.4 Dendrobates galactonotus 'Red'
4.1 Dendrobates tinctorius 'Dwarf French Guiana'
1.1 Dendrobates tinctorius 'Powder Blue'
5.1 Mantella aurantiaca
2.1 Mantella crocea
0.1.4 Mantella madagascariensis
1.0 Ceratophrys cranwelli
1.0 Bufo americanus
0.0.1 Salamandra salamandra
1.0 Ambystoma tigrinum
0.1 Chamaeleo calyptratus
0.1 Phelsuma dubia
1.1 Uroplatus ebenaui
0.0.1 Chrysemys picta belli
1.0 Terrapene carolina triunguis