There are a few companies that are invested in making sure that their products are fairly made. I have found some through internet research and a few were recommended in Timmerman's book. I have not made extensive searches of all of them, but a few seem interesting.
Fair Indigo has a lot of clothes that look like things I would want to wear, ethics aside. The company is based in Wisconsin, and sources from factories around the world. For each item, it tells wear it was made and who made it, guaranteeing that it was made ethically. Many of the factories are family-owned and provide impressive benefits for their workers: a salary well above the local average, paid leave, vacation time, maternity leave, etc. I ordered a sweater from them, and was very pleased with it. Also, their prices seem relatively reasonable, and currently a large portion of their items are on sale.
Patagonia is a company I had heard of previously. They are best known for their outdoor-oriented apparel, although they do make some dressy clothing too. Their prices are high, but the quality is impressive. Their site also includes the "Footprint Chronicles" that "allows you to track the impact of specific Patagonia products from design through delivery." Part of this is the environmental aspect, and part is the ethics of working conditions.
Mountain Equipment Co-Op (MEC) is similar to Patagonia. They are an outdoor equipment company that produces clothing, mostly made in Canada, where the company is based. I was impressed with some performance shirts they had made from the remnants of material in the factories, including the wicking material that is popular in running shirts. These shirts only cost $5 ($4 US) and were made from fabric that otherwise would be thrown away. The only downside to this company is that shipping is rather high and you also have to be the customs fee, since it's being shipped from Canada.
The downside to shopping online is, of course, the environmental impact. It is more fuel efficient to buy from a local store, where goods have been shipped in bulk, rather than having UPS fetch your sweater from Wisconsin and haul it down to NC. However, if our overall purchases are reduced, and we buy sparingly when we need something (I didn't need the sweater, but I'm getting better at distinguishing needs and wants), then perhaps our overall carbon expenditures will be lessened.