While many websites offer great free beginner and advanced German lessons, some of the best include BabelNation, DeutschAkademie (click on "Free German Course" in the left side of the page) and Deutsche Welle. Deutsche Welle is an excellent website that offers lots of German audio, but the website is also in German. Under "Deutschkurse" in the left side of the page, click "Deutsch lernen."
YouTube includes various free tutorials. For example, the "DeutschOnlineLernen" channel offers great tutorials as does "LinguaTV." Also search iTunes for free tutorial podcasts such as the "Germanpod101," which is also offered online.
Organizations that promote foreign relations, such as the Foreign Service Institute and the BBC, may offer online tutorials. Both offer excellent and free audio lessons on their websites. The FSI offers many audio clips. The BBC's courses are offered as BBC: German Steps and BBC: DeutschPlus.
Complete the audio exercises you find out loud. Do so in a place where you will feel comfortable repeating the exercises out loud, such as at home or in a closed room or office.
Use a tape or digital recorder to record you completing the audio exercises. Then compare your recording with the actual clips to check for pronunciation error.