it's one of the most covered songs in history. there are a lot of really fantastic versions out there.
my favourite version is by either Morcheeba or Angelique Kidjo. both by excellent female vocalists who put their own twist on the song.
i can't post links yet, but you can find both on youtube worth a listen! also, if you google 'summertimeweb' you'll find a list of artists who have covered it - there appear to be thousands (!)
i also remember a version i heard some years ago by a band that, if i recall correctly, were from someplace in central/eastern europe. the beat was electronic, and the lyrics were in french and english. any idea who this was? it's driving me mad!
~ edit - my mad google skillz lead me to them - a Lithuanian band called Skamp. it's not nearly as good as i remember it being all those years ago
~
anyway... which is your favourite?