I can only tell you what I did with great results so far (it has only been 11 days):
1) I dethatched (you might not need it - I did).
2) I rented a slit seeder and ran it in two directions. This cuts grooves in the soil and drops the seeds right in.
3) I topdressed with compost and peat moss. I literally just flung it around. With a few waterings, it all settled into place nicely. I also spread some Milorganite, which is cheap.
4) Then I watered lightly 3x daily.

So far, there has been a lot of germination in the spots receiving full sunlight. There has been light germination in the areas receiving moderate sunlight, and no germination to really speak of in an area that doesn't receive much sunlight at all. The places that are receiving the best germination are also the places where I really took my time in spreading the compost and peatmoss.

Having read this board and others for the past year and making a lot of mistakes along the way, perhaps the best thing that I have every learned here was to make sure there is seed-to-soil contact, as well as the value of a topdressing.

As for your weeds, I can tell you my neighbors' experience. Three of them are organic.
1) The guy with the best lawn (It is unbelievable) took care of his weed problem with chemicals before going organic. Now the lawn is so thick that nothing could penetrate it even if it wanted to. Part of me thinks that he must still use some type of preemergent in the spring, but I have been told no. But my point is that he really worked on getting the weeds out first as well as thickening up the grass. So you might want to consider spreading a chemical preemergent for a year so that your grass has some time to fill in properly.
2) The second guy also has a beautiful lawn. Also very green. He just has some clover. There is probably more clover than I would want, but to anyone who drives by it is a really really dark lush lawn.
3) The third guy never overseeded and his "organic" program consists of minimal applications (I think only 1 annually) of organic fertilizer, no weed pulling, no preemergents, etc. His lawn is horrible. I don't even know where to start with him. I dethatched and slit seeded for him the other day, but I think he really needs to apply a preemergent next spring so that we can properly overseed next fall without so many crabgrass plants blocking us.

I guess that seeding this fall, given all the crab grass and other junk, may not be especially productive. On the other hand, I'm willing (and my wife insists) that we do our best, even if it means not getting the best bang for the buck on what we invest this fall. I'm gathering that we should go with a preemergent next spring to set up for a more productive seeding in the fall of 2008.

(On preemergents, will we get a good result with CGM? I'd like to stay organic, but if I'm going to wait all this time, and really try to "do it right" in the fall of '08, I'd like to get the Spring set up to work well...will CGM tamp down the crabgrass and other stuff pretty well?)

With a more structured 2008 plan in mind, presuming we fertilize in the next couple of days (SBM, presumably), am I right that we should wait a couple of weeks before seeding (again, it's still very warm here in Central VA)? And in terms of seeding, what sort of process should we use? Simply scatter seed? Scatter seed and roll it? Rent a slit seeder? It's a pretty big bit of grass, lots of hills and uneven terrain.

Thanks.

I'm thinking that it will make sense to first fertilize (SBM? Alfalfa? I've used both before), and give it a couple of weeks before seeding.

Your absolutely correct. Use both SBM and Alfalfa @ 50lbs per 1000sqft and water in.

You will not get the results you are looking for if you use CGM this year. Not sure if you saw my little tests from a few weeks back, but I didn't see very good results. In fact, the CGM acted as a fertilizer, not a preemergent. When I posted my results, people pointed to research that stated:
1) In the tests where it worked, it was applied over several years.
2) It was applied at a rate much heavier than the average person would apply it.

So, although this is an organic forum, I would suggest that you bend your organic goals for a year and use a synthetic preemergent in the spring. You don't sound like you want to wait 3 years for your lawn to look good. Get the weeds under control with the spring preemergent so you can do a great overseeding in the fall.

Having read all of the overseeding threads in recent months, and having experimented on my own a couple weeks ago, I think my plan outlined above is a solid one. If you don't go with a slit seeder, get an aerator. The very last resort would be to simply scatter seed. I had much better results this year with a slit seeder than I did with an aerator last year.