Thats because C# and pretty much everything cept
VB is case sensitive, so iInt, iint and Iint are all different variable names.
So VS can't autocorrect capitilization for you, I'm not sure why you can't have an option to assume 'if it 'xxx' exists already in the language or defined, then captilize the same as before'...because for beginners it is harder to remember and it must slow down the typing of the code.
One tip though, CTRL+SPACE will autocomplete (or bring up a list if VS is unsure) the word, so typing 'using S' then pressing ctrl+space will put in 'ystem' for you.
Also watch the intellisense that does come up, esp on lines like 'xxx var=new' as intellsense will automattically pick the right bit after the new so you can just type '('