Or, without creating a large list: 
@b=(0,1);@b=($b[1],$b[0]+$b[1])for(2..pop);print$b[1];

[download]
(and there is no reason to assign $a)

20090727 Janitored by Corion: Added formatting, code tags, as per Writeup Formatting Tips

In reply to Re: fibo's 66 chars by Anonymous Monk
in thread fibo's 66 chars by Oromis92

Title:
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and:  <code> code here </code>
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