Recoll downloads
You will probably need to have a look at the installation manual for building and/or installation instructions.
You will need an installation of xapian-core for source builds. You will find source and binary packages on the xapian download page
You need qt 3.3 in all cases
Source
Current version: 1.5.1: recoll-1.5.1.tar.gz. See the known bugs and issues and changes.
Older recoll releases: 1.4.3. 1.3.3. 1.2.3. 1.1.0. 1.0.16.
RPMS
The executables inside the binary rpms have a static link to xapian, there is no dependency except Qt. Of course you need xapian-core installed to use the source rpm.
Fedora Core 4 RPM: recoll-1.4.3-1.i386.rpm. Source: recoll-1.4.3-1.src.rpm
Mandriva 2006 RPM: recoll-1.4.3-0.1.20060mdk.i586.rpm. Source: recoll-1.4.3-0.1.20060mdk.src.rpm
Binary bundles
These are just prebuilt trees (without the source files). The executables were built with xapian 0.9.6 and libiconv 1.9.2 (where relevant) as static libraries. They depend on qt 3.3. For Solaris, you should be able to find a qt package here.
The installation instructions are there.
FreeBSD 5.5 i386: recoll-1.4.3-FreeBSD-5.5-PRERELEASE.tgz
Linux (redhat 7.3, i386). I expect this to also run on more recent systems. The recoll version is a bit old but this may give you an idea recoll-1.2.2-Linux-2.4.18-3.tgz.
Solaris 8 sparc. recoll-1.4.3-SunOS-5.8.tgz.
FreeBSD ports
There are ports for both xapian-core and recoll in the standard tree, you may just need to update your ports (cvsup), or you can get the ports from the FreeBSD site: xapian port recoll port.