that is a very complex matter since Hinduism is the oldest of the main world religions, and is "blessed" with an almost insane ammount of scriptures and written tradition. for a general overview I would very conservatively recommend to try wikipedia:
http://en.wikipedia.org/wiki/Hinduism
Buddhism by some is compared to Hinduism like jesus is compared to the Judaic tradition: both men served as some kind of reformers of the established conservative thinking, and by that were turned by history into founders of parallel traditions that separated from the original lineage. Both men lived at roughly the same time, both men have parallels in thinking, and both men made the orthodox order their enemies. There are religion-scientist claiming that before the timeframe of the four gospels begin (before his 30th birthday), Jesus maybe travelled to India and was influenced by buddhist thinking, which would not surprise me since the parallels between buddha and Jesus (not the church!) are surprisingly unhidden, just that they expressed themselves in different cultural symbols and languages, of course. But that can only be seen if one does not obey the claim that the church dogma represents Jesus' cause.
The most prominent difference is that where Judaism and Christian Church tradition are monotheistic (as Islam, which is the youngest of all these traditions), Hinduism (the oldest) is multitheistic and Buddhism is nontheistic.
For a brief comparison between Hinduism and Indian Buddhism, again simply try wikipedia:
http://en.wikipedia.org/wiki/Buddhism_and_Hinduism
But there are partial parallels between Hinduism and many other Asian traditions as well. Also, Buddhism has many different faces, some are more dogmatic and compare to the superstitious "I give buddha so buddha gives me" exchange trade mentality you often see in the popular beliefs of rural populations whose interest lies in having close ties to their deities so that they do gbet the weather effects they need to have a nice harvest, others are more abstract, or pragmatic, and do not depend on belief in the classical religious sense (Ch'an maybe being the most obvious example). See the "see also" paragraph in the first Wikipedia article. Taoism and Confucianism need to be named here for comparison to Hinduism, since both have developed influence far beyond China. the old Hinduistic tradition of the Vedic scriptures you find practically all over Asia, even if hidden in different terms and names. their cultural influence over the course of history is hard to be overestimated.
Hinduism is the most dominant religion in India, I think around 90%, with Buddhism today just being an almost non-influential subgroup (ranking amongst the remaining 10%, which also are Christians, and muslims). the classcial Indian culture was almost wiped out during the Islamic invasion and conquest from the 10th to 12th century. the modern animosities between Islam and Hinduism, that finally led to the split of Pakistan and the ongoing conflict between Pakistan and India, have their roots in that agression. India'S history goes back almost 9 millenia, and the history of Hinduism goes back at least 5 millenia. Compared to that, Buddha and Christ (2 millenia) are rebellious youngsters almost, and Muhammad (1.5 millenia) a baby.
