Blisk, thanks for that URL; I've got it in my favorites now, so I can keep track of what's going on (HA!). Here are a couple of added thoughts on the listings you gave:

Java Villa Jam
Thu 6 Mar, 2008
Wichita, KS
Weekly on Thursday
Venue is small coffee shop; usually a pretty small group (3-8 musicians); all Irish music. A musician as good as Jed would be most welcome!

Acoustic Jam at Grandma's Farm
Sat 8 Mar, 2008
Wichita, KS
Monthly on 2nd Saturday
Haven't heard of this one. May have to go see what it's about next time.

Old Chicago Jam
Mon 10 Mar, 2008
Wichita, KS
Weekly on Monday
Back room at the Old Chicago Pizza Parlor; usually around 15-20 musicians, mostly Irish music; was a good jam the last time I went to listen.

Kansas Bluegrass Association Jam
Sat 5 Apr, 2008
Wichita, KS
Monthly on 1st Saturday
The KBA has some good musicians in it, but our experience was that they're not too friendly--and if it ain't bluegrass, don't play it. That may have changed since we were there last; it's been a couple of years.

Another one that comes to mind is the Emma Chase Cafe in Cottonwood Falls (it's about 75 miles from Wichita, heading toward K.C.). You can find listings at this URL. It's usually a pretty good jam; you can get some outstanding catfish to eat there, too.

I think these are too far away to do you any good on this trip, but maybe next time...
Walnut Valley Festival (Winfield 2008)
Wed 17 Sep, 2008
Winfield, KS
This festival starts on Wed 17 Sep, 2008 and ends the 21st, but as you no doubt know by now, camping begins about a month before, and jams are common from mid-August thru mid-September. Come join in!

Fun Barn Old-Time Music Festival
Thu 9 Oct, 2008
Winfield, KS
This festival starts on Thu 9 Oct, 2008
Have heard good things about this one, but haven't been yet.

Hope to get a chance to talk with you at the concert.

Lin