Hi Michael.

Create a circular buffer in RAM somewhere to hold at least 1.1 data lines (max length of data line + a few extra bytes). Enable serial input (Interrupt driven), and wait until a CR (Carriage return 0x0D) is received. Then parse the input from this RAM buffer. Convert the received data to bytes and store them at the destination address. After that you decrement the CR counter and advance the input buffer read pointer to the end of the line you just parsed. Then wait for the next CR and repeat everything.
At the same time detect the end of the file. If you find the end of the file you can jump to the start address of your program.

I'm working on a description of different file formats at the moment on my homepage. Look at:

www.bigfoot.com/~sanmail and then click on knowledge base.

Good luck