So, both my PS3 and my PC are on my monitor--Need adapte
Sorry if this message has information you already know.
What model is your monitor?
Your monitor might have two inputs as you said. If it does, there is usually a button or a setting in the monitor that you choose from. This is the ideal scenario. If one is HDMI, and the other is DVI, this is perfectly ok too. But, be cautioned that often times with that style of a monitor, the DVI port does not support HDCP, only the HDMI does. That happened to a friend of mine and he was not too happy about it. If yours is that case, what that means is whatever is plugged into the DVI port if it requires HDCP (the PS3 does, and so can your computer if you ever put a bluray drive in it) it won't work. Yes, an HDMI device can be plugged into a DVI port using an adapter, you just lose audio.
My monitor only has one HDMI port but it does have an audio output so I bought an HDMI switcher from monoprice. The first one I bought didn't work so well so I exchanged it for a different one. It works flawlessly.
Be advised that if you get one with more than 2 inputs, you'll want to ensure you can go to precisely the input you want, instead of cycling through them. This can be done with a remote with individual input buttons, perhaps a push switch for every input, or whatever. But don't buy one that just has a toggle input button where you scroll through the inputs.
The reason for that, is it will very likely cause an HDMI handshake problem, and as a result you will have to turn off and turn on the monitor every time you change inputs. Which gets annoying really quickly.
Mine is an HDX-501 but due to the constant changing models on these devices, as well as the fact that in reality, some monitors can be just finicky with these switches, no one can really guarantee a specific one will work, for YOU. Seriously, trust me on that. Don't get all pissed if it doesn't work at first, HDMI handshaking is just, well, dumb and irritating!
Last thing.......if you end up deciding to buy a switch, don't forget to pick up another HDMI cable. :)