Sony has suggested that it's recently released PlayStation Home will be present on future platforms, although right now the team is just focused on making the service as good as possible.
To quote: In an interview with CVG, Sony Computer Entertainment Europe (SCEE) Home service manager Dan Hill answers that question, stating that Home's potential is almost limitless and Sony sees it having a very long life.
"Home is a brand-new service and no-one else is doing anything of this scale or ambition," said Hill. "Its potential is almost limitless in terms of where it could go. We see it as having a very long and fruitful life."
As for immediate cross-platform plans and making the service available on the PSP, Hill left that prospect open to speculation, though hinted it is something the company is looking into.
"We're looking at possible future directions for the service, but at the moment we're focusing on making Home as good as it can be, and getting content, activities and spaces into the service that are genuinely going to add something to the PlayStation experience, and make it a very special place for our community." More PlayStation 3 News...