If you're looking to mod your PS3 without jailbreaking it, there are a few services you can use. Free PSN Codes is one service that will give you access to modded PS3 games and other content. You can also use PSN Store to download mods for your PS3 games.
There is not a lot of information available on this topic. However, from what we can gather, it appears that there are some ways to mod a PS3 without jailbreaking it. This includes using a modchip or using a software exploit. However, it is unclear how effective these methods are, and it is possible that they may not work at all.
In conclusion, PS3 mods without jailbreak services are not as common as those with jailbreak services. While there are a few ways to get around the need for a jailbreak service, most PS3 users will need to use one in order to mod their console.