The issue is that the dock connector could charge through Firewire or USB. Before the iPhone 3G and 2G touch, all iPods used firewire for charging, so most docks used Firewire.
You can't tell by looking the connector if it will charge via USB or Firewire pins. You have to check with the manufacturer...
Apple has planned to discontinue Firewire charging for several years, and has been warning accessory makers that this would be coming soon. The iPhone 3G and 2G iPod Touch are the first iPods with dock connectors that do not support Firewire charging.
What that means is that MOST charging accessories support Firewire charging for the most compatibility - until now. I suspect you will rapidly see them switch over to USB charging, because it supports the new iPods and only drops support for the 3G iPod.
I did a little more research and find this old review:
http://dev.ilounge.com/index.php/ipod/review/kensington-sx2000-speakers-with-universal-dock/
It talks about 3G iPod compatibility (which REQUIRES firewire charging), so I suspect the speakers will NOT charge the iPhone 3G or 2G iPod Touch. It also shows a special adapter to charge the old Shuffle, which needed USB. The adapter looks like one Belkin used to make that converted Firewire charging into USB.
If I had to guess, I would say that this is not going to charge the 2G iPod touch...