Thanks...
Compiled and worked (not I was expected), but thereīs my fault.

Before interrupts, with a 25Hz signal Iīve read a 1500 rpm.
Now, with led blinking, Iīve read is 120~180.

The code

Code:
'****************************************************************
'*  Name    : UNTITLED.BAS                                      *
'*  Author  : Mauro Perides                                     *
'*  Notice  : Copyright (c) 2008 Mauro Perides                  *
'*          : All Rights Reserved                               *
'*  Date    : 25/11/2008                                        *
'*  Version : 1.0                                               *
'*  Notes   :                                                   *
'*          :                                                   *
'****************************************************************
'@ device pic16F887, HS_OSC, WDT_OFF, LVP_OFF
INCLUDE "DT_INTS-14.bas"     ' Base Interrupt System
INCLUDE "ReEnterPBP.bas"     ' Include if using PBP interrupts

'Define MHZ Crystal
DEFINE OSC 20
' Set LCD 
DEFINE LCD_DREG	PORTB
' Set starting Data bit (0 or 4) if 4-bit bus
DEFINE LCD_DBIT	0
' Set LCD Register Select port
DEFINE LCD_RSREG	PORTB
' Set LCD Register Select bit
DEFINE LCD_RSBIT	4
' Set LCD Enable port
DEFINE LCD_EREG	PORTB
' Set LCD Enable bit
DEFINE LCD_EBIT	5
' Set LCD bus size (4 or 8 bits)
DEFINE LCD_BITS	4
' Set number of lines on LCD
DEFINE LCD_LINES	2
' Set command delay time in us
DEFINE LCD_COMMANDUS	2000
' Set data delay time in us
'DEFINE LCD_DATAUS	50

SYMBOL LED1 = portd.1
symbol rpmIn = portd.0
rpm VAR word

ASM
INT_LIST  macro    ; IntSource,        Label,  Type, ResetFlag?
        INT_Handler   TMR1_INT,  _ToggleLED1,   PBP,  yes
    endm
    INT_CREATE               ; Creates the interrupt processor
ENDASM

T1CON = $31                ; Prescaler = 8, TMR1ON
@ INT_ENABLE  TMR1_INT     ; enable Timer 1 interrupts



:main
    CM1CON0 = 0 ' Comparators off (Do I need these?)
    CM2CON0 = 0 ' Comparators off
    'ANSEL = 0
    ANSELH = 0  ' Configure other AN pins as digital I/O

    output PORTB
    INPUT PORTD.0

    PORTC = 0
    TRISC = 0
    
    
    LCDOUT $FE, 1,   "    prdTURBO    "
    LCDOUT $FE, $C0, "  FUEL COMPUTER "
    pause 2000
    LCDOUT $FE, 1
    
    
    while 1=1
     COUNT rpmIn, 100, rpm 
     LCDOUT $FE,1, "PULS/S ", DEC(RPM)
     LCDOUT $FE, $C0, "RPM ", DEC(rpm)*60
    wend

 
'---[TMR1 - interrupt handler]--------------------------------------------------
ToggleLED1:
     TOGGLE LED1
@ INT_RETURN