Hi, I just write a tutorial about making a very basic Space Invaders using C# and XNA. It earned me 800 pageviews in just over 1 day, so I think It would be helpful for you

. If it's not, sorry for the incovenient, if it is, it would be nice to leave some comment for me

.
Anyways, hope you enjoys it. Welcome any criticise.
http://www.hieu.co.uk