A few useful resources for learning C#:
http://www.homeandlearn.co.uk/csharp/csharp.html
Really simple, and a lot of it can be skimmed.
Some useful pages:
Open a text file using system dialogue, and display it in a rich text box:
http://www.homeandlearn.co.uk/csharp/csharp_s4p10.html
Try, catch, and dealing with errors
http://www.homeandlearn.co.uk/csharp/csharp_s5p6.html
Lists (seem to be a better solution for dealing with arrays of data than arrays themselves)
http://www.homeandlearn.co.uk/csharp/csharp_s7p6.html
Hash tables (associative lists)
http://www.homeandlearn.co.uk/csharp/csharp_s7p7.html
Enumeration
http://www.homeandlearn.co.uk/csharp/csharp_s7p8.html
Another hugely useful book is Rob Miles’ C# Yellow Book. Easy-to-read style and not as patronisingly simple as the homeandlearn course.
Finally, the following book:
C# in Depth by Jon Skeet
(Recommended book by a C# guru, especially for the detail and the reasoning behind these details. But costs £30 from Amazon)