JavaScript (Rhino: 108, Node: 114, Webkit Dev Console: 119, jQuery Plugin: 132)
Rhino is the shortest (at 108 characters) because (a) its print function has a short name and (b) it'll let you assign built-in functions into a shorter variable name. So:
h=10,p=print,m='0',a=Array(h-1),s=a.join(' ');p(s+'*\n'+s+m);while(h-->2){m+='00';a.pop();p(a.join(' ')+m);}
Node.js comes in a close second (at 114 chars) because its print function console.log has a longer name, but it'll let us assign that to a short variable as well:
h=10,p=console.log,m='0',a=Array(h-1),s=a.join(' ');p(s+'*\n'+s+m);while(h-->2){m+='00';a.pop();p(a.join(' ')+m);}
However, the Webkit Dev Console (and probably Firebug, too) thinks p=console.log is a bit too sneaky (when you try to call p(), it'll complain at you). So, we have to lengthen things out to 119 characters:
h=10,m='0',a=Array(h-1),s=a.join(' ');with(console){log(s+'*\n'+s+m);while(h-->2){m+='00';a.pop();log(a.join(' ')+m);}}
(Interestingly, with only saves us a character).
Finally... a jQuery plugin (still tweetable at 132 characters!):
$.fn.xms=function(h){var m='0',w=2,l=['*',m];while(w++<h)l.push(m+='00');$(this).css({textAlign:'center'}).html(l.join('\n<br/>'));}
And you can invoke it on the footer of this very page: $('#footer').xms(3)
Of course, it doesn't have to be a plugin... since we'd probably have to use a JavaScript console to add it to a page and invoke it, we could've just done a snippet of jQuery:
h=10,m='0',w=2,l=['*',m];while(w++<h)l.push(m+='00');$('#footer').css({textAlign:'center'}).html(l.join('\n<br/>'));
which weighs in at a more competitive 116 characters -- in fact, it beats out the other dev console implementation. But, then again, using jQuery and/or the browser's layout engine might be considered cheating. :)
