Normally I would advise staying away from wearing any knit boot, but after finding the Fratelli Rossetti summer knit boot (top left) I was inspired to find more.
Reading left to right:
1 / Fratelli Rossetti suede and leather knit boot from the summer 2010 collection
3 / Urban Outfitters knitted boots - not available anymore, but I really like them
6 / Textile pattern leather boot - not really knit but it fits and there's more patterns