Reading an article about how anyone can publish their own book and sell it through Amazon (and soon iBooks and no doubt other places) it showed how easy publishing material will be going forward. Self-publishing (sometimes called vanity publishing) has been around for a long time and has resulted in a few hits (Eragon, Tunnels and Shadowmancer were all self-published prior to being picked up by a publishing house) it has been a fairly costly business (Shadowmancer author G.P. Taylor famously sold his motorbike to pay for it). Electronic publication may not have the same kudos but it is faster and much cheaper than print.
As with anything where the gatekeepers have been removed, there is likely to be an explosion of content and most of it will be rubbish. That's probably what will keep the publishing houses a necessity, rather than drive them out of business. They'll still be able to pick up rights to books of famous people and skim through to pick out gems they wish to promote, but anyone who wants to publish can quickly and easily and possibly make some money out of it too. Which means a lot more is likely to get published and, hopefully, it'll mean a lot of material that may have not been published (for a variety or reasons) becomes available.
My question has always been, when will an established author go this route and sell direct?