no online for Vita?

have not been able to get on yesterday or today, is there a service problem?

I think so. I was having the same problem yesterday and earlier today. I thought it was my router at first but Internet worked fine on my vita, it was just signing into PSN that wasn't working. I tried it on my PS3 and it worked fine.  To fix it I just went to the playstation site and logged in there.  Once I logged in there it had me agree to some new terms of service thing and after that it has been working fine since.

New T&C for PSN, you have to log in to accept them.  Easier to see on PS3.

You can also do it via the pc store here.

thanks, guys, a bit of a hassle, but got it worked out, can't stop playing Killzone!