Go to playstation's official site and use the icons at the top to navigate there from the main page. You will need an account to access downloads and some special features though.
You can download games for your PSP in PlayStation Network. It will be in the internet section of your psp if you have Official Firmware.
there might be a sims 3 for psp, but if there is there is no official release date
No.
PSP Homebrew is an excellent site for PSP games.
It's not a site as such, you access the PSN from the PSP's menu.
The psp 1000 its the first official psp release from sony so i suppose it should be it. Unless sony has an older inofficial version of psp.
The Playstation Store is the exclusive authorized site to download PSP games
It has a built in browser. It should be on your psp if you are updated to the latest official firmware.
on the playstation store and look at a-z games and some will be demos
an official release date is unknown. it's not even clear if there will be a version for the psp
To access the PSN you need the latest official firmware, which you can do from your PSP's menu bar.
It's not an official game for PSP and is only a beta game