nah you cant stream, well its not a feature which is built in at least
playtv did come with the option where you were able to copy shows onto a USB drive, but its actually against the laws in Australia so they have removed that feature, you are still able to do it however, you change the region to 'other' from 'australia' and you can do it, but due to other reasons technical reasons the max size file you can copy is 4gb, which is equal to about 1hr SD or 30min HD, so if you planned on copying a rugby match it aint happening.
Thats the other thing i should mention, the format which the shows are recorded in are Mpeg2, no dramas except it means that the file sizes are quite massive, you would want to have quite a large hard drvie in your PS3.
The other feature which it has, is you are able to stream over the PS3 wireless card to a PSP, or you can connect to you PS3 through the internet and program recording guides.. Whilst i dont think its a feature which i will ever use, it might appeal to some people.