If you'd like to learn some tunes from me and hear me talk with some other wonderful fiddlers about their approach, check out my online course through Peghead Nation : "Fiddle Styles Workshop". See a preview of what it's like here!
Also on Peghead Nation, you can learn from one of my teachers, Bruce Molsky. He's one of my favorite musicians to listen to, and his repertoire is full of great old-time tunes. If you're interested in old-time bowing (Round Peak style, as Bruce learned from Tommy Jarrell), this is a perfect place to get it.
On the Artistworks site, you can learn bluegrass fiddle from the great Darol Anger. I was lucky enough to have Darol as a teacher too, and I continue to learn so much from him. He's one of the best fiddlers out there, and always entertaining to hear talk. Darol's course, like mine, features many guests (including me!).
If you're a beginning fiddle player, or a violinist new to "fiddling" in general, I recommend learning at Jam With Lauren. Lauren Rioux is a fantastic educator, and her curriculum is straightforward and extremely helpful for fiddlers - beginning, intermediate, and beyond. Her method of teaching how to hear chords (as a foundation for learning how to back up other musicians and how to take solos and make your own variations) is the best of which I'm aware.