Fortran? Do people still use that? There are about a half dozen microcontrollers commonly used by hobbists. The two main ones are PIC and AVR. PIC is more widely documented, but AVR are better (sorry, just stirring up trouble here). I chose AVR for the Assembly Language, and richer instruction set. Like you, my programming was a little out dated, but I was more familiar with 6502 assembly, so figured it would be an easier transistion for me.
Never seen a Fortran compiler, so like me, you might look at what languages seem most familiar to FORTRAN, which would be BASIC and 'C'... lot of choices, huh. Another plus for AVR, the software is free to download, PIC you have to pay for the full version.
Nigel's tutorials for PIC are great, regardless of which chip you are considering, or even which language. Link posted in previous post by Greg. I learned a lot about the hardware side, and chip features like ADC, Timer/counters, interupts, and such. Never used a PIC, or programmed in 'C', and most likely never will. They are that well written.