Absolutely you can get fired for poor spelling. I understand what it is like to rush through typing and misspell a few words here and there, but I make a conscious effort to correct them because in my line of work, what I type is considered a legal document. If you are serious about improving your spelling, you should look into taking a English grammar college course, or maybe even a course on improving typing. Of course, the internet may also have information/tutorials for you on this as well, but if you can't spell properly, then you are not going to be able to locate the right information