Updated: 12/29/2005
SWDev-Compilers
BASIC archives NEW
Lists links to various versions of interpreted BASIC that came with MS DOS. Including: MS Basic, BASICA, GWBasic, and the MS BASIC compiler. [Report a dead link]
http://www.ojodepez-fanzine.net/network/qbdl/

Basic4GL NEW
Flavor of Basic which supports OpenGL 1.1. Creates Win32 EXE files. [Report a dead link]
http://www.basic4gl.net/

BCX , 4,100kb
Basic to C convertor. So you can then compile the C program with a free compiler. Creates GUI apps, with Menu and Msgbox wizards, programmer help files, 200+ sample programs. NEW: easier way to make GUIs. Also at http://groups.yahoo.com/group/bcx/. [Report a dead link]
http://bcx.basicguru.com/

BPP (beta)
Converts Basic code to C++, which you can then compile into an EXE. [Report a dead link]
http://bppt.narod.ru/

Cheesecake Basic NEW
BASIC interpretor for free. 65 commands so it's compact. [Report a dead link]
http://members.tripod.com/~panks/pindex.html

Chipmunk Basic NEW
Claims to be Gwbasic compatible basic interpretor. Main version is for MacOSX but they also have a Win32 version. Tutorials and example code on this page also. [Report a dead link]
http://www.nicholson.com/rhn/basic/

Cygwin
A unix environment developed to run under Windows. Thus you can use GCC as a compiler under this shell. And use other unix software like X windows (xfree86.cygwin.com). [Report a dead link]
http://www.cygwin.com

Dev-C++
From Bloodshed.net. Full C++ compiler for DOS. [Report a dead link]
http://www.bloodshed.net/devcpp.html

Digital Mars 8.27 , 2,900kb
New free C++ compiler for DOS/Windows looks very promising. With integrated IDE and debugger. GUI versions and command line versions of tools. Easy profiler. Win 3.1 API, OLE, MCI, Pen, Sockets and MFC documentation. Includes C++ exception handling and rtti. NO FREE DOCS, BUT THE CD IS $25. Utils:
    * obj2asm.exe Object file disassembler
    * dumpobj.exe Dump object files
    * dump.exe Dump any file
    * dumpexe.exe Dump executable and dll files
    * implib.exe Import librarian
    * rcc.exe Resource compiler
    * smake.exe Advanced make program
    * coff2omf.exe Convert object files from coff to OMF
    * cl.exe Convert Microsoft CL command line to Digital Mars SC
    * makedep.exe Makefile dependency generator
    * libunres.exe Scan library files for unresolved symbols
[Report a dead link]
http://www.digitalmars.com

DJCPP
Dr. Jobbs C++ dev package. Includes a 32-bit compiler for DOS, and much more. There is also RSX for Windows GUI programs. And a debugger called RHIDE. Does not make windows programs by itself. Supports regular expressions via regexec and regcomp. [Report a dead link]
http://www.delorie.com/djgpp/

FreeBasic NEW
BASIC compiler! Requires at least win 95. It has not been tested on Win 3.1 with win32 added on. [Report a dead link]
http://www.freebasic.net/index.php/download

GCC
Currently GCC contains front ends for C, C++, Objective C, Chill, Fortran, and Java as well as libraries for these languages (libstdc++, libgcj,...).

IDEs and GUI libs for GCC are at http://www.xraylith.wisc.edu/~khan/software/gnu-win32/ide-and-gui.html. [Report a dead link]
http://gcc.gnu.org/

GWBasic NEW
BASIC interpretor. [Report a dead link]
http://www.qbasic.com/files/

Ibasic , 1,184kb
Write windows programs with BASIC-like IBASIC. Built in editor and debugger, built-in dialog creator, no external libraries required, full MDI support, 150+ commands and functions, can call external DLLs, structured data types, console support, graphics primitives supported, bitmap, cursor and icon support, wave file support, low and high level IO functions, memory allocation functions. [Report a dead link]
http://www.pyxia.com/softindex.html

LCC Win32 compiler
C Compiler produces Windows executables, not just for a DOS window. Good docs and lots of them! (500+ pages!) [Report a dead link]
http://www.cs.virginia.edu/~lcc-win32/

MingW32 compiler
Headers and libs to use GCC to make applications. Supports Windows and DOS programs and uses Win C runtime (CRTDLL.DLL) http://www.xraylith.wisc.edu/~khan/software/gnu-win32/ [Report a dead link]
http://www.mingw.org

Open Watcom C++ , 45,000kb
Support for the old Watcom C++/Fortran compilers, now free. [Report a dead link]
http://www.openwatcom.org/download.html

Rapidq (beta)
Cross platform BASIC compiler which can make GUI or CONSOLE apps. It compiles all graphics and sound files into your EXE file, no DLLs to distribute. Last release was Aug 2000. Has libs for Mysql, GTK. Supports DirectX but not OpenGL.

You type in text which creates the windows and controls, like TK.

Apr 2002: work has begun on a new version. Site has been inactive since Aug 2000. [Report a dead link]
http://www.basicguru.com/rapidq/about.html

Turbo Pascal to C/C++ converto
Yes. Converts ANSI/Turbo Pascal to C or C++. [Report a dead link]
http://www.garret.ru/~knizhnik/

Xbasic , 5,500kb
BASIC compiler for making GUI systems. CONS: Cannot install in arbitrary directory. No tutorial. Docs mention PDE for making GUI programs but there is no PDE program. No more development. (Look for icon of a window with a hammer on it, that shows the GUI toolkit.) Last release Jun 2000. Also at xbasic.sourceforge.net. [Report a dead link]
http://www.maxreason.com/software/xbasic/xbasic.html