Well, since it's number of seconds elaplsed since 1970-01-01...
SELECT DATEADD(ss, 1345554248, '1970-01-01')
SELECT DATEADD(ss, 1345554580, '1970-01-01')
SELECT DATEADD(ss, 1345554271, '1970-01-01')
SELECT DATEADD(ss, 1345554603, '1970-01-01')
SELECT DATEADD(ss, 1345554033, '1970-01-01')