Yes, as of Connectify Hotspot version 2.0 and later, the Nintendo DSi is supported as a client to Connectify Hotspot networks. To setup your DSi to use a Connectify Hotspot network, go to System Settings -> Internet -> Connection Settings -> Advanced Setup. Choose one of the connections (4, 5, or 6), and then select “Change Settings”. Enter the SSID and password for your Connectify Hotspot, and you will be up and working.

Note that only DSi's built-in browser, and games made specifically for the DSi can use these connections. Games made for older DS versions do not support WPA2 encryption and cannot connect with Connectify Hotspot.