Getting Started
This is a good introduction to FB for QBasic programmers, based on SJ Zero's tutorial.
Getting started with the software
You can download FreeBASIC here: http://www.freebasic.net/index.php/download
And FBIDE here: http://fbide.sourceforge.net/
When installing FBIDE, select "FBIDE only," to not install the old version of FB included in that package.
When running FBIDE the first time, you will have to browse to find the FB compiler on your computer.
Hello World!
Open up FBIDE and type the following:

     PRINT "Hello World!"
     SLEEP

Now press F5. Congratulations, you've just seen how much like QB FreeBASIC really is. Now you can use most console commands for QB just like you remember. For example:

     LOCATE 10,10
     PRINT "I'm the center of the universe!"
     SLEEP

The Amazing Screen 13
Now, put "SCREEN 13" before your code, to see how easy it is to use graphics modes:

     SCREEN 13
     PRINT "Hello World!"
     SLEEP

From there, all of the standard QB graphics commands work as you remember, as you can see in this example:

     SCREEN 13
     LINE (1,1)-(100,100),1,bf
     PRINT "Hello World!"
     CIRCLE (10,10),10,2
     PSET (30,15),3

     SLEEP

FreeBASIC also has new graphics features. For example, QB has never had a screen 14 or greater. Try running this program:

     SCREEN 15
     LINE (1,1)-(100,100),1,bf
     PRINT "Hello World!"
     CIRCLE (10,10),10,2
     PSET (30,15),3

     SLEEP

After opening a graphics window via the SCREEN command, you can also hit ALT-ENTER to change between windowed and fullscreen modes.
Another nice feature of the graphics library in FreeBASIC is that you can do page flipping in any video mode. The following code demonstrates this.

     DIM as integer page
     DIM as integer notpage
     DIM as integer a, b

     screen 12, , 2 'This sets the screen for 2 pages
     notpage = 1   'This sets the backpage

     DO
      IF page = 0 THEN page = 1 ELSE page = 0   'These two lines flip the page and the
      IF notpage = 1 THEN notpage = 0 ELSE notpage = 1 'backpage

      SCREENSET page, notpage 'This flips the page

      CLS  'First we clear the screen
      b = b + 1
      IF b > 100 THEN b = 0
      FOR a = 1 TO 128
       PSET (b,a),a 'Then we draw a line. It moves without flickering.
      NEXT a

     LOOP UNTIL INKEY = CHR(27)

This works for any mode, so you can use the high resolution modes for your programs with page flipping, using standard QB graphics commands!
Why ASM is No Longer Required
I wouldn't be saying this if it wasn't true. Using ASM in BASIC to increase the functionality of your program is no longer necessary. Ignoring SDL, Allegro, DirectX, OpenGL, et. al. for a minute, you've got the above page flipping and advanced graphics modes at your disposal, as well as Inkey, which we've all grown to love or hate, but there are also two new input commands which do things QBers have had to resort to assembly code to do since the dawn of time:

     DIM as integer x, y, buttons
     CONST as integer escapeKey = 1
     SCREEN 12

     WHILE NOT MULTIKEY(escapeKey) 'this checks the escape key every frame
      GETMOUSE x, y, , buttons 'This gets the mouse state
      PRINT x,y,buttons
     WEND

With this knowlege, you should be able to begin programming in FreeBASIC, with all the perks that it entails; Speed, power, and portability!