Just bought a Phottix Odin trigger set and an extra receiver for my A77 and HVL-F56AM and Minolta 5600HS/D. These provide the TTL functionality missing from the Pixel Kings (I contacted Pixel King to ask when the firmware would be updated to A77 compatibility and was told it wasn't going to be).
With these older flashes you still have to set the power output and zoom setting but the camera will meter TTL, newer flashes may be more controllable. My flashes also only allow High Speed Sync if the camera decides that the scene is bright enough but the Phottix units override this giving much improved creativity.
Phottix also produce a flash unit (Mitros+, which I can't find in the UK) which includes their own transmitter/receiver tech.
The only downside was that I had to order from the States as Amazon (only UK listing) were out of stock, but they were here in 3 days. I got them from B & H Photo:http://www.bhphotovideo.com
The dollar price was about the same as Amazons pound price but I did get hit by import duties (£85.52) but I recon I'm about £30 up on the deal even so.
Did plenty of research on Youtube (Gary Fong does a great demo indoors removing background detail with HSS), before taking the plunge.
So if you're looking for TTL remote flash control I highly recommend these units.