The following is the steps I used to build a production quality screen printing table with a built in developing station for the screens. A few of the major pieces are either things I had around, or things that I found. I hope to give you an idea of how to build your own, but keep in mind that I may not be able to give you very good options for some of the supplies.
Step 1: Materials and such.
1 table (if you skipped the words up above this probably sounds dumb)
2 sheets of 1/2 inch MDF
1 sheet 1/4 inch MDF
4 sections of 4x4 cut to the height of the base table
3-4 UV lights with fixtures
2 mending brackets
1 roll of 1/2 inch industrial felt in the size of the table you want to build
1 roll of raw canvas long enough and wide enough to cover table
Black out cloth
Staple gun and staples
Screws, nails, etc.
Small bucket or something, maybe a bowl, or deep saucer... you know, a vessel of some sort.
Maybe a little frilly trim if you're into it
* The felt came from a school that was recovering all of their screen printing tables, and was going to throw it away. Apparently, they do it every few years, so I would recommend asking around at your local art school to see if they do the same thing. I'm sure you could buy this somewhere, probably online.