At this time I'd like to declare UniMRCP can be compiled for and run on 64-bit operating systems as a native 64-bit application.

There were reports indicating UniMRCP successfully runs on 64-bit Linux, though I didn't try it myself before. However, things have been changed recently and I have tested UniMRCP enough on both 64-bit Linux and Windows.

- Linux
Everything is quite straightforward and usual on CentOS 5.3 x86-64 I tried. One should proceed with the regular installation.
./configure
make
make install

It's possible to cross-compile for 64-bit even on 32-bit Linux
CFLAGS=-m64 CXXFLAGS=-m64 LDFLAGS=-m64 ./configure
make
make install

- Windows
Visual Studio itself is a 32-bit application and it's a bit strange to me, but as of today, there is no native 64-bit version. Fortunately, 64 bit tools (compiler, debugger) are available, but those tools are not installed by default, even while installing VS on 64-bit Windows. So if you're going to play with this stuff, make sure you have 64-bit compiler installed.
I have added x64 configuration next to win32 to project files (vcproj) and property sheets (vsprops) in order to compile UniMRCP for a 64-bit platform. Now UniMRCP nicely works even on Windows 7 x86-64.
Corresponding APR and Sofia-SIP project files will be included in the dependency package to be released with UniMRCP 0.9.0 version after the New Year.

Happy Holidays,
--
Arsen Chaloyan
The author of UniMRCP
http://www.unimrcp.org