According to Der Spiegel, both Russia and Georgia have made extensive use of misinformation since the conflict began:
How truth lost the war (‘Wie die Wahrheit den Krieg verlor’)
The two most important points:
Russia claimed that the Georgians had killed 1,500 people in the South Ossetian capital Tskhinvali and turned 98 percent of the city into ruins during their initial assault. Yet, the field hospital near Alagir [in North Ossetie, Russia], where almost all wounded Russians and South Ossetians were brought to, accepted only about a dozen of them that night.
…
Georgia had claimed that Russian tanks were advancing towards the Georgian capital Tbilisi. But on Tuesday evening, there were still no tanks to be seen around the city, when the Russian President announced an end to the fighting
(I had to correct my initial translation in one point due to a misunderstanding, please see the update below).
Der Spiegel also refers to an article in the Moscow Times:
Russian television is flush with footage of misery left by the Georgian assault in the separatist district of South Ossetia, but few, if any, reports mention Russia’s bombing of Georgia.
William Dunbar, a correspondent in Georgia for English-language state channel Russia Today, mentioned the bombing in a report Saturday, and he has not gone on air for the station since.
“I had a series of live, video satellite links scheduled for later that day, and they were canceled by Russia Today,” he said by telephone from Tbilisi on Sunday. “The real news, the real facts of the matter, didn’t conform to what they were trying to report, and therefore, they wouldn’t let me report it.
“I felt that I had no choice but to resign,” he added.
Update: In my original translation, I had written about a field hospital near Tskhinvali, for the wording in the article had led me to believe that Alagir is located near the city. But in fact, Alagir is located in North Ossetia, Russia. This article from Reuters also would suggest that casualties are far lower than reported.