you are in luck im writing a tutorial as i am reading this, on how to use a PIC18F4620 and the "File I/O Functions Using Microchip's Memory Disk Drive File System Library " for SD cards. Its easier than you think since most the code is already made up for you to use it. You just have to disable some non essentials so it can fit on a PIC18F4620 since it only has 64k memory. But if you have a "PIC18F8722" then you can have the full thing working.
I should be done by tonight (like 4-6hours) or tomorrow the latest. Im trying to borrow a camera from a friend to take pictures. It will be in PDF format.
EDIT
Note: 1 Mbit is not 1 Megabyte its way less. In fact:
1 megabit = 0.125 megabytes
which is:
0.125 megabytes = 128 kilobytes
which is:
128 kilobytes = 131,072 bytes
which may seem like alot but 1 sentence like
"Time: 13:23:44 , Temp: 89 Deg F"
thats about 30 characters which is way less than you are actually going to write(i assume).
If 1mbit is enough then your set but then you need to most likely make a terminal or usb program for pc use which would be more work on the pic side to create. Why not just use the sd since its simpler and can be removed and replaced easy and its not expesive anymore. a 32MegaByte chip is like $5 or less. theats 32 MEGABYTE not BIT.
Also a 2GB is like $10-$15 so heh i rather get a TON more for a LITTLE more