The principal Protestant Churches have many similar beliefs to the Roman Catholic Church.
Protestantism really began as a movement to reform Christianity, not to break away and create new beliefs.
For example, Martin Luther, a Catholic priest and professor of theology, at first only wished to reform the practice of selling indulgences, a practice that he believed was corrupting the Church.
After his excommunication, he formed the church which became known as the Lutheran Church, beginning the Protestant Movement.
Protestants believe in the Holy Trinity, and in life hereafter.
Protestants do not believe in praying to saints, the use of indulgences or the existence of purgatory.
They believe that absolution of sins can be obtained by prayer alone.
Catholics believe that grave (mortal) sins need to be confessed to a priest, and like Protestants, they believe that minor, venial sins may be confessed directly through prayer.
Protestants believe in salvation by faith alone (Sola fide) rather than by faith plus its resulting good works of charity.
They believe that the sacrifice of Christ was sufficient for salvation.
Protestants follow essentially the same Bible as Catholics minus the Deuterocanonicals/Apocrypha.
Jesus and the Apostles used the Old Testament with the seven books in question included.
Years after the crucifiction, Jewish leaders, wanting to distance themselves from the emerging Christians, removed seven books.
They kept the books written in Hebrew, and discarded the ones written in Greek.
Today's Protestants use the shorter Jewish version of the OT.
Catholics use the longer OT that was in use at the time of Christ.
The ideas of praying for the dead, and of a place of purging before ultimate entry into heaven are contained within these books.
The longer version was used by all Christians until the time of the Reformation.
Protestants believe that Scripture alone is all that is necessary for spiritual guidance (Sola scriptura). Catholics believe that the use of Scripture plus Tradition ( ideas and practices passed down from the time of the Apostles and the founding fathers) is needed.
Protestants and Catholics observe the same major feasts.
Catholics observe seven sacraments and Protestants only observe the sacraments of baptism and communion.
Protestants believe that communion is to be viewed as "symbol" only.
Catholics believe that the bread and wine, during the Consecration at the Mass become the body and blood of Christ, as in the Last Supper.
Protestants and Catholics have more in common than not.
There are thousands of different Protestant denominations, each with slightly different beliefs and practices.
All Catholics, whether of the Latin (western), Eastern, or other "Rite", share a common set of beliefs.
Arguably Mormons, Seventh Day Adventists and some other Christian groups are also Protestant, however there a greater differences to which the above does not apply.
Sorry got a bit carried away with the info ;D
