Help - I think have been 301 Hijacked

A couple of days ago I noticed strange blog comments on my website. At first I thought it was just someone with poor english skills...

I checked the stats page and there were some odd "terms searched" and "referrals by" - one was a french mobile phone number. I've taken the site off-line, but I'm not really sure where to go from here.

Does anyone know whether it is worth reporting it to Orange (operator of mobile no) and what I should do now. (apart from go to bed as it is half 12!!).

Thanks guys!