There's a slew of general information on TVover.net and IPTV Information.
For general information, definitely check out the IPTV Information FAQ: http://www.iptvinformation.net/IPTV+FAQ.aspx
For general market information, check out the IPTV Reports category: http://www.tvover.net/CategoryView,category,IPTV%20Reports.aspx
Hope that helps.