Phelps attended Christ The King Regional High School in Middle Village, Queens, New York. He was named to the 1990 McDonald's All-American Team. He played in the McDonald's All-American game with future UNC teammates Eric Montross, Brian Reese and Clifford Rozier.
Phelps holds two Tar Heel records at North Carolina for most steals in one game (9) and most steals in a career (247). He was named as an All-Atlantic Coast Conference Honorable Mention in 1993, and was named to the 2nd Team in 1994. He was a member of North Carolina's 1993 NCAA National Championship team. The Tar Heels defeated Michigan 77-71 in the title game.
After college, Phelps has played professional basketball internationally. He played for ALBA Berlin from 2000-2002 with former UNC teammate Henrik Rodl. In the 2003-2004 season, he played for Śląsk Wrocław in Poland's Dominet Basket Liga. He has also played for GHP Bamberg in Germany.