My child can walk now, but he skipped crawling.
Some children go directly from sitting up to cruising and then walking. There has been a small amount of research done on these children, which shows they might have slightly worse hand-eye coordination than children who do crawl. That being said, it is ok if your child does not crawl, as long as you did not dream of him being a professional video game player as an adult! If you want to encourage crawling, try getting down on the floor yourself and crawl; then encourage him to do the same. Make a game out of it, and it won't take him long to catch on.