I've been playing electric bass for over a year now and I'm interested in learning upright. Anyone here play upright, and if so what should I expect? Anything I can do to ease the transition? etc.
I'd definitely suggest to get a teacher. And don't get a plywood bass. Save up for a decent bass.

To help ease the transistion, practice ear training. Being able to hear intervals before playing a fretless instrument helps greatly.

Also, when you get the teacher, make sure he/she teaches both French bow and German bow.
amen to that^

learning to read standard notation will help too
Washburn RB2500 (5 String)
Yamaha BB400 Fretless (1981)
Carlo Giordano 3/4 Upright (White)
Cort Action 4 (Stereo-fied)
Orange Bass Terror 500
Orange 1x15 Cab
Boss GT-6 Bass Multi-effects
Technique is also more important because a lot more of the tone comes from your fingers. Get ready for a bunch of blisters if you play pizz though