Mark told me that the same basic functionality will be represented in product groups in both the Small Business and Small Business Pro lines with one likely exception: Voice will probably be a Pro product line because of the configuration required. I've set up small business VoIP systems and can see the logic behind this plan. It's not really that the networking side is horrifically complicated, but making sure everything talks as it's supposed to with the PSTN (telephone network) can be complicated and require knowledge that most computer networking folks don't have (and don't particularly want to obtain).
It's important to be clear about one thing: The Linksys name is not going away for consumer-level products. It will, instead, be used only for consumer products. If you go looking for a business networking product from Cisco, it's going to have a Cisco label, although it will take a while (there was no hard timeline given) for products with the Linksys name to work their way through sales channels and product life cycles. The end result, for small business network buyers, is another serious option to consider for their network infrastructure.