Although it's not possible to make each new task move to the certain position automatically based on its name, you can quickly sort all tasks within a project alphabetically by clicking on the gear icon at the top of the list (the "Task Actions" menu) and choose "Sort by name".
Thanks for this tip. However, I was looking to rearrange my project list by name (not tasks). I know I can insert projects above/below other projects but I often add several projects at the same time and it would be great if there was a function in which they could be automatically arranged in ABC order. Thanks!
Thank you for clarifying. That's indeed not possible right now, but we may consider adding such option in the future and you're welcome to vote for this request in our Votebox: http://todoist.com/Vote/showProposal/664/