There were lots of Pharisees, including many who believed in Christ. Of the latter, the two named in the Gospels are Nicodemus and Joseph of Aramathea. Paul (Saul) was also a Pharisee and did not give up that title, even after he started evangelizing the Gentiles.
A Pharisee is a particular sect that believes G-d cares about our behavior. They started codifying and encouraging their behavioral approaches after the Babylonian Exile because they were concerned that apostasy had caused the Exile and wanted to avoid a repeat. As history has shown, they failed.
Jesus did attack the leaders of the Pharisees, although study of Pharisee and Jesus' own teaching styles suggest that Jesus Himself was a Pharisee. There was good and bad among Phariseeism and it appears that Jesus attempted to keep the good while rejecting the bad. Matthew 5:20 states (NIV):
For I tell you that unless your righteousness surpasses that of the Pharisees and the teachers of the law, you will certainly not enter the kingdom of heaven.This suggests that Jesus did not see Phariseeism as all bad.
Jesus attacked the Pharisees on two fronts. One was hypocracy. They called for certain behaviors but did not do them. In addition, they focused on trivial details of the Torah (Law) and ignored important provisions. The most striking example of this was their claim that you could declare your posessions "corban" (dedicated to G-d) and thereby avoid taking care of your parents. Thus, in Biblical language, "Pharisees" is a synonym for "hypocrites." Note that, when challenging the Pharisees, Jesus did not challenge their love of Torah. Rather, he challenged their incomplete approach to it. Matthew 23:23 "Woe to you, teachers of the law and Pharisees, you hypocrites! You give a tenth of your spices--mint, dill and cummin. But you have neglected the more important matters of the law--justice, mercy and faithfulness. You should have practiced the latter, without neglecting the former.' (Emphasis mine.) Pharisees were also known for going farther than the Torah required. For example, men were supposed to give the Sabbath over to the worship of the lord and do no labor. Labor hadn't been defined, but was clearly intended to focus on income-producing work. There had never been any law against healing on the Sabbath, nor preparing food such as picking grain for the purpose of eating it. Clearly the Pharisees were trying to put "fences" around Torah. They felt that, if they kept a stricter law than G-d called for, they could be sure that they wouldn't violate the law that G-d had established. If they stayed far away from the sin, they could make a mistake and still not sin. It's kind of like staying far away from the edge of a clif. You can still stumble and not fall over the edge.
Jesus condemned this focus on Torah itself. Torah was given so men could focus on G-d. Torah is a life-giving gift for the Christian as much as for the Jew. But the purpose of Torah is to give this life and to encourage people to live for G-d. The minute they start living for Torah they fail to live for G-d and defeat the purpose of Torah.
I hope this helps.
Shalom.