What do you mean exactly? Old games as in games you purchased on the PSN? If so, all you need to do is register a profile under your PSN ID on your new PS3 and you can simply download all of your previous games/content to your new PS3. Do you mean transfer all of your content from your old PS3 to your new PS3? If so, there's actually a function you can use to transfer all of your data from one PS3 to another so long as both PS3s are connected to your LAN. Just use the transfer utility under settings/system settings. You'll need to deactivate your source PS3 first under account management, then create your profile using your pre-existing PSN ID for your new PS3 and then simply go to settings/system settings and use the transfer utility which will move all of your data from your old PS3 to your new PS3. You will not have your data on your old PS3 anymore. It's unfortunately not possible to move game data from one PS3 to another without compromising trophies and possibly saved game data (some games don't allow this short of using the transfer utility which will make the game data unusable on your previous ps3, though you could probably back up the data beforehand and then use the transfer utility? Don't know...). So only do this if you're not going to be using your old PS3 anymore for your current PSN ID. In which case, your old PS3 can be given to someone else or simply used as a media center or... well, a party PS3, or whatever you want to use it as.
Some saved games that are locked to your PS3's MAC ID won't load up if you transfer them via a USB drive. Always use the transfer utility unless it's absolutely not an option. Even then, you'd do better just visiting a friend with a network for a couple hours. You'll very likely lose progress in a few games. I have hundreds of hours invested in Star Ocean for instance. I would be extremely pissed if I couldn't use my saves. Not to mention your saves won't count toward your trophies anymore on most games on another PS3 without the use of the transfer utility. The transfer utility actually transfers the saved games to the new MAC ID. Without it, most games will assume you simply copied the saved game from another PS3 and are attempting to load it on this one (which in essence is what you're doing). So anyone could copy their friend's save that was a fight away from a very difficult trophy and voila, you get the trophy. That's why the PS3 basically disables trophies for saves that weren't created from that specific PS3.
Anyway, enough rambling. Just use the transfer utility unless you absolutely cannot for some reason. If that's the case, hopefully you weren't too attached to any of your saves.