Well, just take the Olympic Timer as an example and strip it out and refit it to your requirements (after all that's why I created it)... First let's take that interrupt handler and rebuild it to toggle a Flag every minute instead of keeping track of actual Minutes, Hours and Overflow which are unnescessary for your needs....

Code:
	'
	'	Timer Interrupt Handler
	'	=======================
TickCount:
	Gosub SetTimer	
	Hundredths=Hundredths+1
	If Hundredths>99 then
		Hundredths=0
		Seconds=Seconds+1
		If Seconds>59 then
			Seconds=0
			MinuteFlag=MinuteFlag^1
			endif
		endif
	Resume
The SetTimer subroutine can be simplified to junk the Calibration value like so...
Code:
	'
	'	Subroutine Loads TMR1 values
	'	============================
SetTimer:
	T1CON.0=0
	TMR1RunOn.Highbyte=TMR1H
	TMR1RunOn.Lowbyte=TMR1L
	TMR1RunOn=TMR1Preset+TMR1RunOn
	TMR1H=TMR1RunOn.Highbyte
	TMR1L=TMR1RunOn.Lowbyte
	T1CON.0=1
	PIR1.0=0
	Return
Finally we lose our entire Main program body, Reset Code, Calibration Set-Up, and all the unnescessary subroutines, EEPROM settings etc etc leaving us just your desired application... and if you notice the main body is pretty much the exact code that you've written... so in effect you were already 99.9% of the way to your own solution...
Code:
	'
	'	Software Defines
	'	----------------
	Hundredths var BYTE
	MinuteFlag var BIT
	Seconds var BYTE
	TMR1RunOn var WORD

	'
	'	Software Constants
	'	------------------
	TMR1Preset con $D910

	'
	'	Start Program
	'	=============

		'
		'	Initialise Processor
		'	--------------------
		'	Put your TRIS and Register initialisation statements here

	MinuteFlag=0
	Hundredths=0
	Seconds=0
		'
		'	Initialise TMR1 Interrupts
		'	--------------------------
	Gosub SetTimer
	On Interrupt goto TickCount
	PIE1.0=1
	INTCON.6=1
	INTCON.7=1
	'
	'	Main Program Loop
	'	=================
	Enable

Begin:
	let portb.0 = porta.0
	If MinuteFlag=1 then goto LoopXXX
	goto begin
loopXXX:
	let portb.0 = porta.1
	goto loopXXX

	Disable
Just remember that no command in your Main Program Loop can exceed 10mS execution time otherwise you will lose your timing integrity (program won't die, but you won't get a 1 Minute timing interval for the Flag to toggle, it'll be 1 Minute plus the number of 10mS interrupt ticks you've missed).

If accuracy in your minutes is important to you, adjust the TMR1Preset constant. Increase the value to speed up by 100uS per minute, Decrease the value to slow down by 100uS per minute (at 4MHz clock).

See... easy peasy... don't be afraid to take any of my code and trash it into anything that you need... it's posted for you to learn from.

Melanie