It seems the SMB market will be a big play in 2006 for the VoIP industry. I've previously mentioned that companies like CallTower, Covad and Speakeasy are nicely poised in the space.
Others have made noise as well. According to a Vonage spokesperson I spoke with recently, the long awaited Vonage SMB play seems to be on hold while they get their act together with the VARs they have been trying to assemble. Their product offering, what was to be reportedly a IP-PBX developed by the Sipura team inside Linksys in the meantime is coming out from Linksys who more than likely will try to assemble their own group of ITSP's.
One things for certain, the market will certainly grow. New businesses have little reason to start with legacy PSTN. Others looking to modernize will shift to VoIP and as the prices fall for the hardware, and minutes too, this can be a huge growth opportunity. Expect a lot of "sham" companies to get into the space too.