Well, this is from Tacitus (Annals 15.44) He's talking about Nero blaming the Christians for the fire in AD 64.
"Consequently, to get rid of the report, Nero fastened the guilt and inflicted the most exquisite tortures on a class hated for their abominations, called Christians by the populace. Christus, from whom the name had its origin, suffered the extreme penalty during the reign of Tiberius at the hands of one of our procurators, Pontius Pilatus, and a most mischievous superstition, thus checked for the moment, again broke out not only in Judaea, the first source of the evil, but even in Rome, where all things hideous and shameful from every part of the world find their centre and become popular."
http://classics.mit.edu/Tacitus/annals.11.xv.html
There's a number of other sources as well, but this is probably the most well-known non-christian source, particularly that near to Christ's time.