Roll 4d6, add up the total, compare to either of these tables for result.
Rolling dice needs to be exciting. There's something magic about that moment when the dice hit the table, and you immediately know if things have gone in your favour or not. Using this method you've got to actually calculate your result. If I roll d6s (six sided dice) and see a table full of sixes I want to instantly know either that it was a great result or (depending on the system) a terrible result.
I think, for those without Fudge dice I would recommend any of the following methods:
1) Buy some. You've just spent $90 on a roleplaying game. By comparison buying a set of dice for $6 is cheap. You could even spend $20, buy one of the Fudge GMs packs and have dice for the whole table.
2) Buy d6s with pips and use a permanent marker to turn them into Fudge dice (
http://www.fudgefactor.org/2001/12/01/babys_first_fudge_dice.html)
3) Make your own fudge dice out of cardstock or light cardboard (
http://www222.pair.com/sjohn/sprkdice.htm)
But if you really are averse to fudge dice
4) Use d6s - treat 5 or 6 as +, 3 or 4 as blank and 1 or 2 as -
There are also a variety of d6 based methods which produce a different curve, but it doesn't really matter so long as everyone on the table uses the same method.
5) Use two different coloured d6s. Define one as positive and one as negative. Roll d6-d6 and treat results of +5 or -5 as 0
6) Use two different coloured d6s. Define one as positive and one as negative. Roll them both. Treat a matched pair or set of a 5 and a 6 as 0. For any other roll take the value of the lowest number showing. If its on the negative dice its a negative result.
7) Add 7 to all difficulties in the game and roll 2d6. Treat Double 1 or Double 6 as a roll of 7
The advantage to all these methods - as soon as my dice hit the table I know if its a good result or not.