After you dial in, click on Start, then Run. Type telnet. Open a connection to icarus.uic.edu.
If your Windows installation is so old that it doesn't include telnet, download the ACCC NSKit.
Windows includes editors, but it doesn't include a compiler, so you need to install one. I recommend MinGW, a Windows version of gcc, because I've heard that the installation is very easy: download gcc-2.95.2-msvcrt.exe, run it, and tell it to install in C:\GCC-2.95.2. You can then compile and run foo.c inside a DOS window by typing
PATH=C:\GCC-2.95.2\BIN;%PATH% gcc -o foo foo.c fooYou can use MinGW to build graphical programs. See the MinGW FAQ for more information.
Other free Windows compilers: Cygwin, another Windows version of gcc; lcc-win32, another UNIX-style compiler; and Borland C++ Compiler 5.5.
There are many free flavors of UNIX: Caldera Linux, Corel Linux, Mandrake Linux, Red Hat Linux, FreeBSD, NetBSD, OpenBSD, etc.