Pre-release software is built using actively developed sources. Binaries are built nightly, and minute-by-minute changes are available through Subversion.

Option 1: Installer
Binary distributions PLT Scheme MzScheme PLT Scheme Full
Windows plt-4.0.2.5-bin-i386-win32.exe (22M) mz-4.0.2.5-bin-i386-win32.exe (5.2M) full-4.0.2.5-bin-i386-win32.exe (29M)
Mac OS X (PPC) plt-4.0.2.5-bin-ppc-osx-mac.dmg (38M) mz-4.0.2.5-bin-ppc-osx-mac.dmg (6.3M) full-4.0.2.5-bin-ppc-osx-mac.dmg (57M)
Mac OS X (Intel) plt-4.0.2.5-bin-i386-osx-mac.dmg (38M) mz-4.0.2.5-bin-i386-osx-mac.dmg (6.3M) full-4.0.2.5-bin-i386-osx-mac.dmg (55M)
Mac X11 on Darwin (PPC) plt-4.0.2.5-bin-ppc-darwin.sh (36M) mz-4.0.2.5-bin-ppc-darwin.sh (6.0M) full-4.0.2.5-bin-ppc-darwin.sh (53M)
Linux/Fedora 7/x86_64 plt-4.0.2.5-bin-x86_64-linux-f7.sh (37M) mz-4.0.2.5-bin-x86_64-linux-f7.sh (6.1M) full-4.0.2.5-bin-x86_64-linux-f7.sh (55M)
Linux/Fedora 9/i386 plt-4.0.2.5-bin-i386-linux-f9.sh (36M) mz-4.0.2.5-bin-i386-linux-f9.sh (6.0M) full-4.0.2.5-bin-i386-linux-f9.sh (54M)
Linux/Ubuntu plt-4.0.2.5-bin-i386-linux-ubuntu.sh (36M) mz-4.0.2.5-bin-i386-linux-ubuntu.sh (6.0M) full-4.0.2.5-bin-i386-linux-ubuntu.sh (54M)
Linux/Ubuntu Feisty plt-4.0.2.5-bin-i386-linux-ubuntu-feisty.sh (36M) mz-4.0.2.5-bin-i386-linux-ubuntu-feisty.sh (6.0M) full-4.0.2.5-bin-i386-linux-ubuntu-feisty.sh (54M)
Solaris plt-4.0.2.5-bin-sparc-solaris.sh (37M) mz-4.0.2.5-bin-sparc-solaris.sh (6.0M) full-4.0.2.5-bin-sparc-solaris.sh (54M)
Source distributions PLT Scheme MzScheme PLT Scheme Full
Windows plt-4.0.2.5-src-win.zip (17M) mz-4.0.2.5-src-win.zip (5.8M) plt-clean-tree.tgz
Macintosh plt-4.0.2.5-src-mac.dmg (15M) mz-4.0.2.5-src-mac.dmg (4.5M) plt-clean-tree.tgz
Unix plt-4.0.2.5-src-unix.tgz (15M) mz-4.0.2.5-src-unix.tgz (4.4M) plt-clean-tree.tgz
(version 4.0.2.5, updated at Tuesday, July 22 2008, 03:26 EDT)

Installers:  
PLT Scheme
Same as the normal distribution, containing the basic systems (MzScheme, MrEd, and various libraries), and DrScheme.
MzScheme
A small distribution that contains only MzScheme and console applications based on it, including the PLT web server. No docs and no GUI applications.
PLT Scheme Full Repository
Contains the complete PLT tree from Subversion, including full documentation, full source tree, libraries that are not completely stable, and esoteric material.
Note: the default installation directory contains the version number to avoid clobbering a normal installation. Under Windows, registry names are different, too.

Option 2: Subversion

Full source is available from our Subversion.

Option 3: Other

Want Scheme sources from Subversion but don't want to build binaries? Want to browse a Subversion checkout? The nightly build page has everything you could want.