Here is a portion of Talmud Sanhedrin which discusses these signs:
http://www.neveh.org/winston/parsha58/shavuos_5758_part_1.htmlRebi Yochanan said: In the generation that Ben Dovid will come, talmidei chachamim will decrease, and the eyes of the remainder will protrude from sighing and sorrow; many chastisements and many evil decrees will be renewed; one will not cease before another begins.
The rabbis taught: The Shmittah period in which Ben David will come the following verse will be fulfilled in the first year, "And I caused it to rain upon one city, and upon another city I caused it not to rain." (Amos 4:7). In the second year, slight famine will be sent. In the third year, a great famine from which men, women, and children, pious and deed-doing people will die, and Torah will be forgotten by those who learned her. In the fourth year, some will be satiated, and others will not be. In the fifth year, there will be great satiation, with eating, drinking, and joy, and Torah will return to those who learned it. In the sixth year, voices [speaking of the Moshiach's imminent arrival] will be heard, and in the seventh year, there will be war [Gog u'Magog]. In the year after the seventh, Ben Dovid will come. Rab Yosef said, "Many Shmittah cycles have come and he did not arrive!" Abaye answered, "Were there voices in the sixth year followed by war in the seventh year? Secondly, did they follow this order?"
Rebi Yehuda said: The generation in which Ben Dovid will come ... The wisdom of the scribes will be corrupted; men fearing sin will be hated; the leaders of the generation will have the nature of dogs; and truth will be lacking ... He who turns away from evil will be regarded by the public as being foolish.
Rebi Nehorai taught: The generation in which Ben Dovid will come the young will embarrass the old, and the old will rise for the young; a daughter will rebel against her mother, a daughter-in-law against her mother-in-law, the leaders of the generation will have the nature of dogs, and a son will feel no shame when criticized by his father.
Reb Nechemia taught: The generation in which Ben Dovid will come, insolence will increase, respect will be missing ... and all the governments will turn to false beliefs (minnus); criticism will be of no avail.
Ben Dovid will not come until informers increase ... And hope in the redemption is renounced. (Sanhedrin 97a)