I've dealt with this a few times, both in my live group and in my online game, both with groups of more or less random people who met through a service to play, and with friends from school/work/life. I have handled it well, and I have handled it incredibly poorly. You learn a lot from those mistakes, but it can hurt.
There are a lot of variables you haven't mentioned, too many to give you a single answer. For example, are these friends, friends of friends, strangers you met on the internet? Are there any real world issues which might be interfering? Are there any group dynamics which might result in spillover to the rest of the group if you boot one player?
However, there are a few general thoughts which might help, and a few common factors to keep in mind for every situation.
Be clear about what you want from your players, and make sure you have a clear understanding of what they want from you. Make sure any real world issues which might affect the schedule or time together are known. Job, transportation, smoking, medication, blood sugar issues, etc. Ideally, do this when you form/join the group, but it's never too late to have that conversation with the entire group.
As a real world example, one of my players has a job which occasionally makes him work late without much notice. So sometimes he will be an hour late with maybe 15-30 minutes notice. It's not in his control, and it's a known issue, so we account for it.
In all cases, it's important that you make clear, proactive efforts to communicate. Again, this ideally begins when you first form/join a group. "Hey guys, attendance is important to me, and so is keeping the cross-talk to a minimum during play. Is everyone cool with that?" But again, it's never too late to begin effective communication.
Effective Communication is always an ongoing process. It's never over. Don't assume there are no problems from week to week; make sure there are no problems by checking in with everyone. At the end of one session, ask if there are any known issues for the next? Give Joe a chance to mention that convention he's attending, or his brother in town. Be proactive, don't just assume the others will remember to tell you about stuff that's still a week away. Ask.
Invite and accept feedback on your GMing. This might seem unrelated, but I've seen players lose focus when a game isn't holding their attention, but too afraid to hurt a friend's feelings by telling them, so the result is cross-talk and more frequent absences/lateness.
Address the Issue
When problems do crop up, communication is even more important. Very little gets resolved by not communicating. Talk to the player in private. In-person is preferred in most cases. Honestly explain the issue, and keep an open mind. This is the time you might get unexpected news or feedback.
When you discuss the problem the first time, after you explain the issue, invite solutions. Don't impose one right away, simply ask if he has any thoughts. I had a new player apologize, telling me she thought the schedule would work, but it turned out to be a problem for her, and she bowed out gracefully. It's not common, but it happens.
Hopefully this fixes the problem. Joe bows out, or sees your point and agrees to be more respectful of everyone's time. Bam. Done. But a lot of the time that doesn't actually work, or it works for a while before Joe reverts to old patterns. When this happens, it's time to dis-invite Joe.
Once more, privacy and speaking in person is best in most cases. Be honest, be firm, be reasonable. "Joe, I've asked you to stop disrupting the game, and you haven't. I'm not going to invite you back. I hope you're not upset, but that's how it is."
Now might be the time you get an earful. Just be ready, and stay calm.
Ultimately, each player has a responsibility to the group as a whole to help ensure everyone has fun. The GM often takes the brunt of this, but each other person has a role too. Use the tools given here and by others to help players understand this when possible, and to remove players who can't contribute to the group fun when you must.