At the same time PostgreSQL 9.2 beta 1 was released, so did pgAdmin 1.16 beta 1 (with an unfortunate copy/paste error on the URL to download beta 1).
We don't have yet installers for Windows, and packages for Mac OS X. They will come at a later time.
What you can expect from pgAdmin 1.16 is complete compatibility with PostgreSQL 9.2. All the new features of PostgreSQL 9.2 are handled by pgAdmin 1.16. You can use pgAdmin 1.14 with PostgreSQL 9.2, but you won't get all the new parameters, and objects. Moreover, you'll have issues with the tablespaces node (one column disappears in the pg_tablespace system catalog).
One thing you shouldn't expect from pgAdmin 1.16, and I'm really sorry about that, is the database designer. This really cool tool isn't ready for prime time yet. We still need more time to fix the bugs, to make sure it's usable on every plateform, and to do all the little things that make a product great. You can still try it if you want, but you'll need to compile pgAdmin (look for the --enable-databasedesigner ./configure option).
I'm working right now on a visual tour for 1.16, but it may take some time before it gets out.
During the beta period, I'll also fix the bugs testers will encounter, and work on the documentation.
So, as you see, still a lot of work. But don't hesitate to install pgAdmin 1.16 beta 1, search for bugs, and report them on our mailing lists, so that we can have a really great 1.16.0 release.