Hi JenBug:

1) Jersey: You definitely do not *need* one but it's nice to have pockets on the back, which is why I end up wearing a jersey most of the time on the bike, even for my commute, so I can keep important items (keys, wallet, cell phone) in my pockets instead of my panniers. I am pretty sure you can find something that suits your taste and body shape.

2) Shoes: I find that cycling for any significant distance (more than a few kilometers) in my regular running shoes (soft soles) is really uncomfortable and gives me foot pain, sometimes lasting for a few days. This is especially true if there are hills involved. However I am fine cycling with my hiking shoes (much harder soles). I have a pair of "touring" bike shoes that are a bit stiffer. They have cleats under them but I can use them with a platform pedal, and to walk short distances. However for very long, fast or hard rides I much, much prefer my really stiff shoes (Sidi Dominators), but these are not very good with platform pedals.

So the bottom line is that you might feel some pain with your trainers, but you'll discover that as you train for your ride. If you plan to get automatic ("clip-in") pedals eventually, then you could get bike shoes now and just add the cleats later. If you don't, then maybe just a stiffer shoe will do, or even your regular trainers...