Based on my calculations the current network rate of the namecoin network is only around 65 GHash/sec looking at the number of blocks found in the last 24 hours.
I look up the current dificulty and estimates at
http://dot-bit.org/tools/nextDifficulty.phpI didn't see anything on that page for total network hash rate. Also I think their numbers are skewed because of the rapid decline in miners after the difficulty switch.
There isn't a total hash rate. But it does show what the current "instant" difficulty of the network is (13'586.66) and the next Difficulty change, which has been changing as mining capacity is reduced. Currently 26/10/2011 06:47 (only 3 months to do what took 3 days last week)