In his new book, Men Deserve All the Advantages, Pope Benedict XVI says male prostitutes can use condoms without going to Hell—er, "without going to Hell as quickly as they will otherwise." Women prostitutes still aren't allowed.
The article says that the translation is unclear about whether he meant male prostitutes in particular or all prostitutes - and in Italian translation they used the feminine form of "prostitute."
Anyway, if it is male prostitutes he was talking about he's being consistent.
Catholic teaching is that condoms should not be used for contraception. They have nothing against them before used for any other purpose and in the case of gay sex they certainly wouldn't be being used for prostitution.
Of course, this gets murky if a woman (as happens fairly often) hires a male prostitute as part of a threesome with herself and her boyfriend/husband. (Unless, as also happens fairly often, she hires him because she's always wanted to see her bf/husband with a dude.)