I feel that the best way to get close to Phil's style is to listen to and watch videos of live Dead. That way you can hear his style and see how he plays. Its a very melodic style and he never plays most of the songs the same way twice. Two good songs to listen to are "Eyes of the World" and "Help on the Way".
What gotmule? said x100.
I got into the Dead late in the game (early 1990s) and "Help On the Way" from One From the Vault was my entry point/gateway to Phil's style of playing.
He has a habit that is very hard to intentionally cop - he often sneaks back at the last possible moment to play a root while in the middle of doing something melodically tangential to but supportive of the main progression of a song without losing the unique pulse and line he was exploring.
I was only able to do it when I consciously stopped trying to do it and it opened up my own playing in fascinating new directions.
There has never been a more Zen bass guitarist than Phil.
