NikonUSA started shipping D7000 kits to its regular dealer base last Friday (typically via UPS). They should start showing up on dealer shelves today. Best Buy jumped the on sale date at many of their stores (Best Buy distributes from their own central warehouses, and had already started to do so late last week).
So, technically, the D7000 kit should be available today, though due to UPS delivery schedules that could be early in the day in some places, late in the day in others, and may spill into tomorrow in still others (plus some stores need some inventory processing time before it shows up in their database as available, especially if they get their deliveries later in the day).
If you're waiting for a body-only version, I'd say expect to wait another month, as that's the typical lag between kits and body-only versions for Nikon. If you can't manage to grab one of these first shipments, I'd say expect to wait at least a couple more weeks, maybe more. If you're outside the US, it appears that Nikon is staggering initial deliveries amongst subsidiaries, probably because the Thailand plant hasn't been building D7000's for long, and there's no inventory build-up to ship simultaneously with.
My current estimate is that only about 10,000-12,000 D7000 kits are being distributed in the US by Nikon at the moment. Given that there are a bit over 3000 authorized places that sell Nikon gear in the US, that suggests that the average store is going to get less than half a dozen to sell (I'm accounting for some who don't get any because they're on credit hold or for other reasons). By the end of the week I should have some better numbers on this.
The good news? If you're looking for an 18-105mm lens there should be a lot of new ones hitting eBay this week, so you should be able to get a decent bargain on one (the implied price of the lens in the kit is US$300, while the street price of the lens has typically been about US$350). In the US, make sure that you get warranty paperwork and 4-year warranty extension form with the lens if you buy it from someone splitting a kit. While technically Nikon warranties aren't transferrable, I don't think NikonUSA has any way of tracking lens+body together, so if you file the 4-year extension card the lens will likely be associated with you, not the kit purchaser. No guarantees here, but it doesn't hurt to try.