Microcontroller I/O configuration

I think Wouter had the right idea, but you need to put CMCON = 0x07; to turn the comparators off (see p.258 of datasheet, top right)

I agree with Olin that there is no substitute for reading the datasheet, but for someone new to micros in general, specific examples are also very useful. The problem (as hinted at by Olin) is many App notes can assume knowledge of x and y and can be badly written or promote bad practices, so it's usually best to treat them as a starting point rather than the final word on the particular subject.

There are a few good books around for PICs, so have a look around and maybe pick up a couple with good recommendations (I can only think a few by Lucio di Jasio but he mainly writes about the 16 and 32 bit PICs)

Website wise, I think the Gooligum tutorials may be just what you are looking for. I have heard it well spoken of and recommended many times on the PIClist (the author is also a member there)
I have not looked in detail, but it appears there is plenty there on the 8-bit baseline and midrange devices, presented in small tutorials on covering various things like:

1. Basic Digital Output Introducing XC8 and CCS PCB Simple control of digital output pins on baseline PICs

2. Reading Switches Reading and debouncing simple switches and using internal pull-ups

3. Using Timer0 Configuring and accessing Timer0 Using Timer0 for event timing, background tasks, debouncing switches, and counting (with some examples of C macros)

4. Sleep Mode and the Watchdog Timer Using sleep mode, wakeup on change, and the watchdog timer on baseline PICs

5. Driving 7-Segment Displays Single and multiple 7-segment displays, lookup tables and multiplexing on baseline PICs (using the PIC16F506)

6. Analog Comparators Comparators, fixed and programmable voltage references

7. Analog-to-Digital Conversion and Simple Filtering Analog-to-digital conversion (ADC) and calculating a moving average (accessing banked memory)