There are several types of congressional committees.
Standing Committees
Standing committees are permanent committees that attempt to tackle issues in congress. The Senate has sixteen committees, while the House has twenty-two.
Subcommittees
Subcommittees are committees within standing committees. They go more in depth than the whole subcommittees.
Select Committees
Select committes are not permanent like standing committees, and they deal with issues that aren't being handled by standing committees.
Joint Committees
Joint committees are committees that contain members from both the Senate and the House. They're designed so that the two bodies can work together to solve a problem.
Conference Committees
Conference committees meet when the House and Senate pass different versions of the same bill. The goal when they meet is to work out a bill that pleases both bodies.