OK, I found the answer, so here I will post a complete guide how to make a sound file into a set of numbers, suitable for loading into a look-up table. Hope it will be useful for somebody.
1. Create or open a sound file in Cool Edit pro (versions 1.0-2.1 will work)
2. Press "Save as" and choose .txt file as an output. The out file will have numbers, but much greater than 1 to -1
3. Copy all the values into the clipboard.
4. Open Excel and paste all the values.
5. Now it is time to remove the empty cells (caused by line changes in the txt file)
6. Select all the cells, press Edit>Go To>Special, select "blanks" and press OK Now all the blank cells are selected
7. Press edit>delete to delete the empty cells.
8. Now, in a new cell, type a constant by which you want to divide the data values (in case of a 16-bit sound file the constant is 32767)
9. Copy the cell with the constant into the clipboard.
10. Select all cells you want to process.
11. Press Edit>Paste Special, select "Divide" and press ok.
12. Done!! The values are ready!
Now please if anybody could enlighten me, how to copy all those values into a look-up table and also which blocks will I need to play this table values? Sorry Brett, I know those are most probably sill questions, but please help - I am just a pianist.