First of all, Pentecostals are not a denomination. They are a tradition that includes many denominations. Charismatics, who have similar beliefs to Pentecostals but are less dogmatic, are found in many non-Pentecostal churches, including Catholicism.
That may be what your friend meant by Pentecostals being “close to Catholicism,” in the sense that Catholic charismatics have a Pentecostal-type experience. Because Catholicism believes in the possibility of miracles and private revelations and so on, there are ways in which Pentecostals are much closer to Catholicism than many other forms of Protestantism are (though Pentecostals have had an impact on the broader Protestant world in this respect). Also, Pentecostals generally do not believe in “once saved always saved” and some Pentecostals have a doctrine of sanctification that is closer to Catholicism than that of many Protestants.
I don’t know where PaulDupre gets the idea that Pentecostals as a whole believe that all true Christians speak with tongues. The non-Trinitarian “Oneness Pentecostals” may believe something like that, but most Pentecostals do not. Rather, they believe that after accepting Christ as savior, one should seek for the “baptism with the Holy Spirit” which results in speaking with tongues. Most Pentecostals have no problem accepting people who believe in Christ but don’t speak in tongues as their fellow-Christians.
Historically, Pentecostals originated at the beginning of the 20th century. The first Pentecostals belonged to something called the “holiness movement” (which is also my heritage, though my people rejected Pentecostalism). This was a movement within Methodism which taught that people could be “entirely sanctified” in a second experience after conversion. The early Pentecostals added the “Baptism with the Holy Spirit” as a third experience after sanctification, and some Pentecostal churches (Church of God, Cleveland; Pentecostal Holiness) still teach this. The majority of Pentecostals, however, came into the movement from other forms of evangelicalism (Baptist, Reformed, etc.) and did not adopt the “holiness” teaching. These “Finished Work” Pentecostals are the mainstream of Pentecostalism today (the Assemblies of God, for instance). The third major group of Pentecostals are the “Oneness” Pentecostals, who teach that Father, Son, and Holy Spirit are different manifestations of the one Person, Jesus. (Yes, this is a revival of an ancient heresy.)
Pentecostals are one of the most varied and divided groups in Christendom (I’ll bet that a good number of the “33,000 denominations” or whatever the figure is now are Pentecostal). They range from TV evangelists like Oral Roberts and Jimmy Swaggart to tiny rural churches; from charismatics who are very open and ecumenical to virulent bigots who denounce other Protestants, let alone Catholics, as false Christians. They have a strong appeal to African-Americans, Hispanics, and people in the developing world. A large proportion of Latin America is now Pentecostal. They tend not to put a lot of emphasis on doctrine or organization–the one thing they have in common is a strong emphasis on personal experience above everything else. So you really can’t generalize too much about them.
I hope that was at least somewhat helpful.