You can use CaptchaTrader (FREE), DeathbyCaptcha(PAID) or decaptcher(PAID) to solve them. I personally use the first and free service, which is very fast and good. You solve captchas and earn credits: +7 credits for 1 captcha you have solved and -10 credits for 1 captcha solved for you. System is simple and effective :)
1 hour of solving captchas can earn you enough credits for a whole day (or two)!