Shapely 1.2.4 has been tagged (see http://github.com/sgillies/shapely/downloads). Sdists are available from http://gispython.org/dist and http://pypi.python.org/pypi/Shapely/1.2.4. This releases fixes bugs involved with loading the libgeos_c DLL/SO and generally improves the user experience in the case of not being able to load them, if you can believe that. If you try to import from Shapely without GEOS on your system, you get:
>>> from shapely.geometry import Point Traceback (most recent call last): ... OSError: Could not find library geos_c or load any of its variants
Also in 1.2.4, AttributeError is raised when you call a GEOS-backed method that isn't supported by your OS's geos_c version. In 1.2.3, you'd see IndexError if you called either of the linear interpolations methods with GEOS < 3.1. Exceptions are part of the API, too, and these changes make the API a bit more user-friendly.
No available geos
Author: Reinout van Rees
Not having geos available isn't so strange. I normally work on linux, but had to install a (geo) django website on windows a few weeks ago. In combination with oracle.
Problem: I couldn't find a geos .exe installer for windows. In the end I had to install postgres+postgis to get my hands on a geos dll ;-)
Re: Shapely 1.2.4
I saw that you'd blogged about that here and I forwarded it along to people on Twitter. Shapely's Win32 installers include the GEOS DLL, so Windows users don't have this problem, but it's possible to install Shapely on *nix systems without the library. In the previous version, it would fail in that case, but with cryptic errors.