As an aspiring yogini, I am often online checking the timetables of local yoga studios, even though I can't afford them right now. However, truth be told, getting to a class and practicing asanas (the physical part of yoga) has generally been more of a velleity than fulfilled. I find the philosophy of yoga very interesting and so I've delved into that quite assiduously, but when it comes to the different styles of yoga asanas my understanding is a bit muddled.
Kimberly Wilson, my go-to guru, offers a great little summary of the most popular styles. Try and ignore the biases that are so obvious, she's a strong follower of yin yoga or vinyasa. Here is the link.