Sony released a brief statement in Japan today announcing an open beta for Playstation Home to start this fall.

Sony says to expand the closed Playstation Home beta this Summer allowing more PS3 users in.

In February Sony still claimed a release date for Playstation Home for the PS3 some when in 2008. With an open Beta starting in Fall of this year a full release will not happen anymore in 2008.
There are no real reasons stated why Sony is delaying Playstation Home. Sony just says that it will give developers more time to improve the Playstation Home services.
Details of the Closed Beta testing features, registration for the test and the opening of the service will be announced as they become available.
Via the Sony Playstation site (Japanese). Update: Sony now also issued an english language press-release about the Playstation Home News.

Sony showed off the Playstation Home the frist time in March of 2007. Back then the company still claimed a release date of Autumn 2007. Now we are looking at 2009 as release year for Playstation Home.