I think is the best free online OCR, supports a lot of languages such as: Bulgarian, Catalan, Czech, Danish, Dutch, English, Finnish, French, German, Greek, Hungarian, Indonesian, Italian, Latvian, Lithuanian, Norwegian, Polish, Portuguese, Romanian, Russian, Serbian, Slovak, Slovene, Spanish, Swedish, Tagalog, Turkish, Ukrainian, Vietnamese.
Supported files are JPG, GIF, TIFF BMP and PDF but only first page of the PDF document. The restriction is to that the images must not be larger than 2MB and a limit of 10 image uploads per hour. You don’t have to register or to tell your e-mail address and that’s good.
The only annoying thing is the CAPTCHA code but they say: “We are sorry that we have to annoy you with this captcha. But this service was abused by spammers who used it for captcha breaking.”.