Hi
1) Case:
I bought this one off the internet:
http://cgi.ebay.com/Leather-Case-Olympus-Pen-E-P1-E-P2-E-PL1-EP1-black-/160450259299? pt=US_Camera_Cases_Bags&hash=item255b94a963#ht_4103wt_931
If that link doesn't work, key in "Leather Case for Olympus Pen E-P1 E-P2 E-PL1 EP1 black" in the search in ebay. It's made by Oprima. First time I bought from them -- shipping was pretty fast considering it came from China (about 10 days including weekend) -- not real leather but didn't expect it to be for $30. Comes with a neck strap that's long enough to cross sling & shoot in that position (if you have EVF). Top portion is removable. This case also fits the camera with the Oly kit 14-42 lens (but not with filter on, which is not a major problem for me cos mostly I go out top off or just put on filter when ready to shoot) & of course pancake, prob not the 40-150 (I don't have that).
2) Camera bag: maybe last thing you need right now is another bag to add to the bag(s) you carry for the kids. Just use a ziplock bag to put camera in and any soft pouch to put extra lens in -- these can then go into kids bag; or lenses can go in coat pocket (kit lenses are small & light enough).
3) Wrist strap -- can use one from existing P&S if you don't want to use camera case.
4) Filters: I know many people advocate using good (expensive) filters but I think that's great if you are aiming to be a very good photographer for the art's sake (and no disrespect to anyone aiming to do that) but if you are aiming more for good family memories, then start with basic filters and then go for the really good ones when you are ready for that direction. So I got 2 filters for my kit 14-42mm at B&H photo (on the web) -- Tiffen UV Haze 1 & Circular Polarizer, together for $36. B&H is a great store -- have bought from them a few times -- never a problem. B&H has got lots of camera stuff, maybe too much
5) Shooting kid's sports: see this thread
http://forums.dpreview.com/forums/readflat.asp?forum=1041&message=37906475
Sports photography is not easy (especially without specialized lenses which are expensive) -- but don't get discouraged -- while they are kids, you can still get good shots if you understand the limitations of your camera system. The good thing you have going is you mentioned soccer & baseball -- outdoor and more chance of sunny weather (indoor volleyball or badminton would be quite a challenge)
6) favourite website:
http://www.digital-photography-school.com/
7) If you still have energy left, try practising indoor lower light shots to get ready for kids' parties before they happen. Although getting the Pana 20mm 1.7 could be the easy way out, I'd say try it with your kit lens first both with and without the flash -- this way you are forced to learn your current kit's limitations and strengths.
8) Other accessories
- Get more memory cards -- 4 to 8GB is enough -- better to have more cards with less memory each than one card with huge memory (all eggs in one basket=trouble) but get class 10 cards for video
- Get spare battery (altho official EPL2 battery is not out yet) -- I find it sucks up battery power quite fast
- Pana 20mm 1.7: what can you say about this lens that's not been said? Small, sharp, sexy light.
- Viewfinder VF-2 -- expensive but depending on how you shoot, this could be a must-have or no-need; I find it indispensable.
- rocket blower for sure -- simple & effective lens cleaner
Good luck, and post your pix for advice here -- most people are very helpful!