Yesterday, I talked about blocking out that pesky daylight, so that you can get consistent results. Here's a little more information about the rest of my photo "stuff."
I could use softboxes, but I actually kind of prefer umbrellas for strobes. They're a little more portable, for if you are ever going to leave your house and work on location. I bought this set from Cowboy Studio and it's working really well for me.
The little squarish thing you see in the second photo is an optical flash trigger. This is not a fancy one. It's a cheap one ($12). In a darkened room, it works very, very well. In a bright room or outdoors - it may not.
You can buy really nice radio triggers, which will work every. single. time. I love them. They cost about $250 for a set and you need at least two, one for the camera and one for each flash you want to use. If you're in the market for those, I used PocketWizards for my entire photojournalism career and they were always wonderful. But, I'm not doing that sort of work anymore or trying to light up entire stadiums, so the price tag is keeping me away.
Some flash units have triggers built in. These can be either radio or optical and they are usually pretty good. My newest flash has radio capability, but my camera's too told to use it! So, I'm totally fine with my $12 fix to keep everything working together.