Not quite, if you believe the Guardian, and I wouldn't necessarily believe everything I read:
Julian Assange attacks 'rubber-stamp' warrant as he loses extradition battle | Media | guardian.co.uk
If you can't be arsed to read the whole thing, the relevant bit is as follows:
The most serious of the four allegations relates to an accusation that Assange, during a visit to Stockholm in August, had sex with a woman, Miss B, while she was sleeping, without a condom and without her consent. Three counts of sexual assault are alleged by another woman, Miss A. If found guilty of the rape charge he could face up to four years in prison.
Personally, I don't believe that this has the ring of truth about it.