Estonians are buying up Georgian wines in a show of support. Best thing you can do, really - guaranteed to benefit the Georgian nation rather than any political movement, so it is good irrespective of any doubts you might have as to who caused what. In conflicts such as South Ossetia, no side is ever completely innocent. I recommend the Akhasheni Marani, should be available in Selvers - a very good semi-sweet red.
Parliament is about to go into an emergency session to draft a joint statement on Georgia. An emergency session can be called with support from no less than a fifth of the Riigikogu (21 members). The session has been endorsed by all represented parties, except for Keskerakond. Vilja Savisaar's official statement to the press was, let's wait and see and gather information and not rush into things. Wouldn't do to piss off the Russians.
UPDATE 1: Meanwhile, Ansip is trying to get to Georgia. Might just be PR for now, but if he does show up in Thbilisi, that'll be a great move on his part. Compensating for political ineptitude with personal bravery; could be worse, and he's doing the right thing when it counts. A commenter on Postimees: "When the Russians came here, did anybody help out?" That is exactly why we need to be involved in Georgia.
UPDATE 2: There is a humanitarian aid flight being put together by Estonian Air, the Red Cross and various other local relief agencies. The Estonian Reserve Officers' Association is apparently putting together a team of 90 volunteers that will be on the flight and will distribute the humanitarian aid, as well as help out relief efforts on the ground. The email that I saw specifically mentioned that the group would absolutely not be involved in combat, but otherwise should be prepared for anything, including hostile fire. The email also says that perhaps the presense of Estonian reservist volunteers in Georgia will serve as inspiration to NATO. I haven't really heard of the group before, but it is certainly a good sentiment.
2 months ago