In addition to the Volunteers Needed listings here on the site, also search the Teams directory by 'medical / health care.' And join and post in the Facebook group Medics for Greece, http://www.facebook.com/groups/135609506795670/
Speakers of Arabic, Farsi, Kurdish, Urdu and more are needed all over. Many of the camps are a majority of one nationality. Please see www.bit.ly/howtovolunteeringreece (work by skill set) for a chart of camps organized by majority language.
Also of course see the Volunteers Needed section of this site for specific calls (check the 'language' box when searching) and search the Teams directory for other organisations that need translators but which may not be actively recruiting.
Short answer: yes. As for where...it's hard to say in advance, as the situation changes frequently. Please prep by reading http://bit.ly/howtovolunteeringreece. You can safely commit to buying a ticket to either Athens or Thessaloniki, then adding on tickets to specific destinations later.
Reach out to various organizations, but understand that administrative support is limited, and you may not get a response immediately if your planned trip date is more than a few weeks away. It's stressful, we know...but trust that plans will fall into place and you will be useful in the end.
There are so many talented volunteers with great skills--but very few admins, and no one with the capacity to sift through a huge list of volunteers and their skills and trip dates.* This is why we leave it up to you to read the Volunteers Needed listings and browse the Teams directory to see what groups are working where, and decide which might be a good fit for you.
(*Group coordinators: We don't mean to underestimate you; we're just basing this on past experience. If a volunteer database would be useful to you, please let us know: firstname.lastname@example.org.)
Yes, definitely! This whole response has been driven by regular people with energy and time to commit. See the "volunteer starter kit" page on this site, particularly the main Google doc.