This is a scam that has been plaguing oDesk for years.
It is against oDesk's policies to work on this.
Flag the job offer as inappropriate and stop communicating with this client in any way.
If you mess around with this you will:
a) waste a lot of time
b) never be paid money from these people
c) quite possibly have your identity stolen and your accounts compromised
d) quite possibly be suspended from working on oDesk
are you people talking about cptcha entery project,even i have been offered such kind of work, where our task is to enter a captha. idont know is that reliable or not ? please guide