There’s a lot going on with this topic these days. I have some pretty good experience in some aspects of the current use of video, but am certainly not an expert in all aspects.
There are two basic ways to go about this; the many DSLRs with video, or a standalone camcorder. I do both.
DSLRs have the advantage of being typically less expensive and very useful for stills as well. They also typically produce a better image in regards to the depth of field look, except for cameras like the Scarlet or the new Canon motion camera.
A dedicated camcorder has the advantage of being much easier to use for video and writing to better codecs. I was quite amazed when I acquired my XF300 how much easier it is to shoot video with the proper shooting aids, that are available on most video cameras. I thought motion and stills were similar enough that it wouldn’t make much difference, but once you film for the first time with peaking, a common motion focusing aid, you will see that there is a real difference.
There are three basic uses a photographer can have with his motion; stock, behind the scenes videos for blogs and the like, and producing an actual story piece with the video. Most of my experience up to now is either with stock or behind the scenes. Stock isn’t that much different than shooting still stock, except you really need something to be moving to make it an interesting clip. Don’t go for too fancy regarding camera moves, etc. with stock clips. The only thing that really frustrates me with stock footage is for footage formats that won’t import into Lightroom, there isn’t anyway I know of to deal with the metadata as efficiently as Lightroom. Thus, this whole process is far more time consuming than with stills.
There is much debate whether video will help the photography industry. I’m not sure, I see both sides of the argument. I do know that it can be a rewarding pursuit, however. There are times when I will become almost entirely focused on video and others when I am almost forget I have the capability; depends a great deal on the subjects I’m working.
If you have more interest in this pursuit, I suggest you check out Vincent Laforet.