Ah sorry for not updating this blog for so long! But today, I bear bad news.
Probably if you want to watch subbed Sentai, you go to youtube, or just download those from TV-Nihon. For some of the older series, you usually go to youtube. But just lately, youtube has taken down A LOT of Sentai episodes and even suspended accounts that stores many of such videos. Most famously, DtKingdom's account.
I have no say on this one. You probably will have to deal with downloading through Megauploads or just go with RAWs. My say: Just do it. Sentai isn't really heavy on mind screws and all, and even if you only understand a little in Japanese, you can understand the story with the raw videos. If you still want to dig more infos, there's a lot of info in wikipedia, and Sean's blog should be of a great help to help you understand Sentai more.
That'll be all I say for now.