A rather easy way is to rightclick on a type and the shortcut menu will give you a "resolve" option, which will add the necessary "using" option. You'll still have to add the reference to the project.

>Yikes. Sounds great, but 349.00 per user license for a commercial license for an add-in?
>
>
>>>(C#)VS2005
>>>I was attempting to create an ArrayList (not permanent, will use a List, but this was for play) and it did not show up for me in intellisense. I went to help and found out that I needed to add
>>>
>>>using System.Collections();
>>>
>>>How do I know which namespaces I need to add when I'm looking for something specific? How do I know which classes belong to which namespaces?
>>
>>
>>You can read it in Help, which shows you the classes, but the best you can and should do is use ReSharper which will do many, many good things for you, one of them, it will tell you you are missing namespaces like in your example and will ask you if you want it to add them for you. :)