It is not that easy to purchase Microsoft Visual Studio 2008. But any platform that uses Microsoft Embedded CE will need VS 2008 for development.
MSDN Subscription
The easiest (and most expensive) way to get a copy is with an MSDN subscription. Here is a link to the MSDN Subscriber VS 2008 download page. Click on Details to see exactly which subscriptions make VS 2008 available.
BizSpark
If you have a company that is “less than 5 years old, is privately held, and earns less than $1 million annually“, you qualify for Microsoft’s BizSpark for Startups. This will give you access to VS 2008, among many other things. Definitely worth checking out if you qualify.
eBay
The final alternative is to search for a used copy on eBay. That is how I got my copy.
Free Trial
But you do not need to decide right away to get started. You can download a free 90 day trial version of Visual Studio 2008 here. That will download an iso file that you will need to burn to a disc and install, or use a program like WinRAR to extract the files. Here are the steps for the second option.
Using WinRAR to Install VS 2008
Once the VS 2008 iso image is downloaded and WinRAR is installed, open WinRAR and drag the iso file into the WinRAR window. This will show you all of the files contained within the iso image.
Then find the autorun.exe file and double click to install it.
Then follow the instructions to install the program. If asked what environment to optimise for, select C#. You should run Microsoft Automatic Updates after installing, and expect this process to take some time.