The earlier you start research the better it will look for you. The key here is finding someone that you can work with who is encouraging and interested in mentoring. There are plenty of professors out there who will gladly give you some menial task in their lab that will make you hate research. Start looking now and try to find someone who will work with you to develop your skills in a specific field. It helps if you are already interested in a particular field.
You need to have that class show up throughout your undergraduate term. It will not hurt you. A's in research can only help you. (and, speaking as a graduate student, not all professors will give you A's. I had to do lab rotations my first year and received several research B's not because my work was inferior but because the professors I worked with didn't like my "motivation." Needless to say, avoid anyone who you think will grade you on anything other than the quality of work you do.) It will be especially beneficial for you to pick one professor and work on a project with that person long term, over the course of several years/semesters. This could lead to publications which will basically, if everything else on your application is decent, guarantee you admission to at least one graduate school. On top of that, you will develop a close working relationship with a professor that you can't otherwise get as a student -- this type of relationship will often lead to shining letters of recommendation. And, if you get the right lab with the right funding, you may have opportunities to travel to various talks and conferences and possibly even present your own work.
The other advantage of doing undergraduate research is that it will put you in a peer relationship with graduate students. This puts you in a situation to reap the knowledge of not only the professor you work for but also his/her graduate students, who often have a fresh and interesting perspective on academia and can give you the kinds of personalized advice you won't get anywhere else.
As for including them in your GPA, don't worry about it. Your cumulative GPA is totaled by your institution, not by you. You may decide to do a separate "major GPA" calculation if your school doesn't provide this, but either way those courses will be included.
The only way it will look bad is if you get a 'C' and then you stop doing research. That can be avoided by judicious choice of professor. Perhaps you could ask senior students who the good professors are to work with.