You'd be surprised. Being small isn't always such a disadvantage. Yes, it does mean more time on the seesaw and more effort over the jumps, but a small dog can turn more tightly and be more effishant on course, saving time and effort that way.
BTW my article on agility was published in this months issue of The Yorkshire Terrier Magazine. There are photos this month of MACH 4 Desi (who came in 2nd in the AKC NATIONALS THIS YEAR!), Mach Hurrican Harley and My Mr. Cinnamon Bun (OA, AXJ, NAC, TBAD, CGC, IQI&II). Tried scanning it but unfortunatly my scanner dosn't seem to like the magazine!
If you want to learn more about agility, I'd did my best to provide an overview in that article. Also will be posting more info on the mightymite website in the near future as well as an "interview" with Desi!