Is there the 64-bit version of Visual Studio?

No, there are only 32-bit versions of Visual Studio at the moment. As Rico Mariani, the leading Visual Studio developer, writes in his blog, this is determined by several reasons.
The main issue that does not let the developers to create the 64-bit version of Visual Studio is the amount of code that they would need to port to a new platform. Porting the main studio's units will force the programmers to port all the existing extension packages for the tool as well. Benefits that will be gained from this high-cost process are not very obvious at present. Most Visual Studio units will not get any significant benefits after the port in comparison to their 32-bit versions while the requirements for physical memory the studio will have while loading large projects might greatly rise because of the increase of data structure sizes in the 64-bit version. But even in the current Visual Studio versions, there is a problem related to long loading time when opening large projects and the increase of memory consumption will just make it worse.
The existing 32-bit versions of Visual Studio can perfectly function in 64-bit operating systems, while usage of 64-bit compilers allows us to create 64-bit programs.
So, creating a complete 64-bit version of Visual Studio will be extended throughout several releases, and the process itself will be performed iteratively with alternate porting of the most demanding units. But this all in no way prevents you from using Visual Studio when creating 64-bit software nowadays.

References

1. Rico Mariani's Performance Tidbits. Visual Studio: Why is there no 64 bit version? (yet)
2. Discussion at Stackoverflow.com. Visual Studio 64 bit?