Here's how I did mine:
Milled pilsner malt and white wheat malt. 7lb or so total, IIRC.
Heat my mash water, mash in at 148 and let it go until it gets down into the 120's (Mash tun is an igloo cooler).
Through a cup of un-milled pilsen malt in.
Flood the headspace of igloo with CO2, and close.
Check every 8 hours or so to make sure it keeps about 100 degrees or so. Add hot water to bring it back up to temp if needed (I also threw in a little more grain... since it was open). Re-flood with CO2 and close.
I tasted it every time I opened. It went from not really sour at 24 hours, pretty sour at 36, and whoa! this is damn sour! at 48. That's where I stopped. Because I kept O2 exposure to a minimum, I got only a clean sour smell and taste. Smelled a bit like sour cream.
Got my runnings from the mash tun like any other brew. Didn't need to batch/fly sparge as I got my full volume from mash tun (due to adding hot water every time I opened the tun).
I boiled for 15-20 min. with 8 grams of hops. This killed the lacto. Cooled, racked to carboy and pitched regular sach. yeast - I used dry S-05, but would like to try a German strain next time.
Fermented all the way to 1.003 with no trouble in under 2 weeks. Had a bit of lag at begining, prob. do to acidic nature of wort.
Put it in a keg, force carb'd it, and done. 2 weeks grain to glass.
It's a very tart (even compared to 99% of commercial examples I've had) and refreshing beer. Mine ended up a little high in ABV (4.8%) in comparison to style guidelines.
I'm going to repeat the process this coming week, but after fermentation is done, rack the beer onto a bunch of peaches.