lighting
 

Ok. i want to plant my 20 gallon long pretty soon. Ive been to my lfs and they don't have lights that i need. also, im not 100 percent sure on which ones i need myself. can someone help me on choosing a light and where to get it. im planning on having a low light plant tank. having some dwarf anubias and java fer & moss. and maybe some dwarf hairgrass. thanks for the help.:-D

Check out Doctorsfosterandsmith.com
They have great prices on lighting!
Also, they give a brief description of the lights and what they are best suited for.

All of the plants you listed can do well in low lighting conditions, so you shouldn't need anything too fancy. What sort of lights do you have now? I think you'd be fine with something like a double tube T8 fixture (with the appropriate bulbs, of course).

how many watts of light would i need, estimated?

I think two T8 tubes would probably give you a total of 30 or so watts. Of course, you'd want to make sure you have appropriate bulbs in the 6700K temperature range for optimum plant growth.

If your hood is not a double bulb fixture, you could always pick up a fixture at a place like Home Depot and then just put the right bulbs in. That's what I did for my 29 gallon ;)