I soon hit upon using iCal on my mac. I assigned different colors to the sources and it is very easy to move posts around. If you look below, you will see my schedule for February of this year with blue representing library books, green for Netgalley, orange for books I own, and pink for Amazon Vine books. Purple stands for these Sunday "ramblings" posts.
This is a great method for me as I always blog from my laptop and thus always have easy access to my calendar unlike when I had a paper calendar that I would have to remember to bring with me when I traveled if I wanted to keep track. It is also zero mess for changing the dates of posts.
It's not perfect; I haven't figured out a way to note which reviews are done and which are not so I have to consult my drafts section in blogspot but that's not too bad. I am also using the To-Do list section of the calendar to remind me of what books still need to be read. But so far, this is the system that works best for me.
How do you schedule? Or, if you don't schedule, how do you work out your posts? Any tips for iCal or other recommended (free) programs?