Yes, the _frame feature at psd2css Online is awesome. Just use Photoshop to draw the whole background to some text or CMS content and name that layer with the '_frame' Layer Naming Convention. Viola - the _frame will expand and contract fluidly with your content.
But... what if you want another _frame under that one? And another _frame under that one? By default the top frame just writes over the lower one on your page. That's no good.
So you know the old saying 'Where there's a will (or a whole bunch of users asking for it) there's a way!'
We made a minor change to the way the _relative feature works along with the _frame feature. So now you can just make a whole stack of _relative_frame layers and as long as they're all inside a container layer it works! On the left, you see 3 _frames with content. The 3 frames are inside an _empty container layer (check the PSD file to see how they are laid out and named). You can test it on this page by clicking below. See? All you have to do is ask many, many, many times, and it will happen :)
Actually - that's what makes psd2css Online great - you all letting us know what you need it to do. Keep it up and thanks!