I also have the same problem, in fact I got a Playstation 3 for Christmas, had all the right cables, and hooked it up to my Samsung LCD LNT-2642H tv. I hooked up everything then turned on the tv to find the HDMI Input. Nothing was found. Confused, I checked the cables. I have an HDMI 1.3a cable and I thought my tv only supported HDMI 1.1 & 1.2. I even called Samsung to find out if my tv could be upgraded via firmware to take 1.3 cables. They said that it was a physical part, not a firmware issue. Saddened, I looked online and then found that my tv does INDEED accept 1.3a cables. So I thought that maybe the Playstation 3 has to be turned on in order for the signal to be recognized by the tv (my impression is that when the Playstation 3 is in standby mode, light is "red", it does not have a constant connection like the Wii), the tv recognized the Playstation!
I have noticed that if I leave the Input to HDMI and turn off the tv, then turn off the ps3, the HDMI Input remains. However, I noticed that when I turn the tv on first (leaving the Input to HDMI) and then the ps3, i have the same problem you do. However, when I turn on the ps3 first, then the tv, I have no problems.
I personally believe there is no problem with the playstation nor the tv; instead I think it is just the way how the ps3 functions with the tv. Have you tried turning on the ps3 first, then the tv? Does the screen blackout during playback? And is your sound through the HDMI too or do you have an optical cable?
I have owned the PS3 40gb and Samsung A650 46" LCD TV since June of this year. I have had problems with the tv while hooked up via hdmi with the ps3. While playing games or on the home screen of the ps3 I randomly get static display, black screen, input not found, and the right side of the tv looks like a barcode, along with audio static but not at all instances. This does not happen at any set interval only randomly. I have been through 3 different hdmi cables. I have replaced via warranty with sony the ps3. I still have this problem. I cannot determine if this is the tv or ps3 that is the problem. Or if it is just the signals getting crossed between the two. I have used the different hdmi ports as well. This does not happen with other componenets hooked up hdmi either. I have found others that have the same problem on different forums. Any help would be greatly appreciated. I have already contacted samsung and they were going to replace the main circuit board without even coming to look at it first. I dont want my tv opened up if it is just a setting or two I need to address. Samsung is saying this is not a widespread issue so please contact them directly via the 800 number given in your manual to make them aware. I am down to the last of my patience with these two components, but really what do you do? I have now changed out all cables, used every port available on the TV, tried to turn the TV on then the PS3 and vice versa, exchanged the PS3, used others PS3's, tried configuring the PS3 to many different settings for video and audio, and lastly updated both software and applied patches to both units. It seems like this is a wide spread issue that Samsung and Sony might want to look more into during their testing.
Also find: http://forums.cnet.com/5208-13973_102-0.html?forumID=146&threadID=313479&start=0&tag=forum-w;forums06