Teaching yourself vis basic? Alot of people say it's a bad place to start, but I started on it and I haven't gone to far wrong (I hope) however if you start playing with vis basics syntax it's quite confusing to change to C, which I'm working on now.
If you're sticking with Visual Basic I suggest a good book, I learnt it through the school and that was pretty easy however it was a while ago. From memory VB has quite a good help menu, it actually makes sense! If you ever want to move into C I recommend Beej's programming tutorials (Just google them)
As for SQL Injections, perhaps http://www.securiteam.com/securityrevie ... 1P76E.html
I think thats the one I learnt from, it looks like its worth reading.
For further learning post here asking something specific, PM me or use google. Google's your best friend!