Bids for 2020 will likely be placed in 2011. The Olympics will also be held in 2020, but current International Olympmic Committee (IOC) rules prohibit a city hosting both a world's fair and an Olympic games in the same year.

BRISBANE LINKS:
How about Briz 2020 - news article
Proposal: the Brisbane Expo 2020 Olympiad

COPENHAGEN LINKS:
Copenhagen Wants to Host the World Fair - news article
København vil huse verdensudstilling- news article, in Danish

DUBAI LINKS:
Dubai proposes to host World Expo in 2020 - news article
Dubai: Olympics and World Expo 2020 - news article

HOUSTON LINK:
Houston 2020 - a proposal

MANILA LINK:
Manilla, Celebrating Life and Light - a proposal

MONTREAL LINK:
Vision Montreal leaders wants Expo 2020 in Montreal - news article

NEW YORK LINK:
New York City 2020 - a proposal

RIO DE JANIERO LINK:
Depois dos de 2016, a Expo 2020 - new article, in Portuguese

SAN FRANCISCO LINK:
2020 World's Fair - a proposal

SÃO PAULO LINK:
Spin City - news article

THAILAND LINKS:
TCEB to bid for World Expo 2020 - from The Nation (Thailand)
TCEB wants World Expo - from Bankok Post

USA LINK:
Expo 2020 USA - site promoting multiple cities