Considering that the version of iTunes that Apple releases is usable from XP all the way to 7 shows that they have been working hard to make sure that your hardware works properly with your operating system in regards to driver support. As well, there are frequent updates to iTunes for all three active Windows operating systems, and some of these issues address compatibility issues not only with the operating system, but sometimes with Apple hardware, too.
Apple Software Update, which comes when you install iTunes, normally notifies you whenever an update is available. But if you want to check for updates, you can do so manually. The program is located in the Start menu under All Programs. The list of programs is alphabetical, and is not included in any folders in the Start menu, so it should be near the very top once you get into All Programs.
For the most part, there shouldn’t be any serious compatibility issues in the move from Windows Vista to Windows 7, or even from Windows XP to Windows 7. iTunes and iPod are fully compatible with Windows 7, either 32-bit or 64-bit. But keep your programs updated, as some fixes include compatibility issues.