You need a compiler, a plain text editor or IDE, and resources/references.
Compiler: There are two big compilers out there. The first is gcc which runs on Linux and *Nix systems. It has a windows port called MinGW. The second is Microsoft Visual C++, which is windows only. gcc/MinGW is free. Visual C++ is not, but you can get a free "express" edition.
Editor/IDE: There's a bit more variety here, but I'll assume you're on windows. There's three choices worth mentioning for an IDE. The first is Visual Studio which costs quite a bit of money. The second is Code::Blocks, which is free. The third is Dev-C++/wxDev-C++.
Finally, get yourself a real book. Accu (http://accu.org/index.php ) has a list. The site doesn't seem to be working ATM, but when it does, take a look at the book reviews for Beginner's C++. My choices go to C++ Primer by Lippman and Accelerated C++ by Koenig.
MinGW: http://www.mingw.org/
VC++ Express: http://msdn.microsoft.com/vstudio/express/visualc/
Code Blocks: http://www.codeblocks.org/
wxDev-C++: http://wxdsgn.sourceforge.net/
I've omitted a list of plain text editors, and since there's so many, please Google.