No problem.
As far as training them to LIKE the carrier, I used real pieces of turkey (it was right after Thanksgiving two years ago when I got Teddy, haha). I tossed the turkey into the bag and let the bag rest against the leg of a chair or something so it wouldn't fall over, and waited for him to decide on his own to get in the bag. If he climbed in and decided to sit there, I just continually fed him treats by dropping them into the bottom of the bag so that he had to put his head down to get them.
Then I started to say, "Get in your bag" while pointing to the bag while it had a treat in it. That was his cue to go after the treat in the bag. Pretty soon he would get in on his own happily, and I can barely keep him out of his bag now.
When not training, I just kept the bag on the floor and open so that he could go in whenever he wanted. Sometimes I'd hide his toys or treats in it so that it was always a pleasant experience. I started training him to get in the bag when he was 12 weeks old-- it was one of the very first things I ever taught him, because I wanted him to like it.