Index: ext/socket/udpsocket.c
===================================================================
--- ext/socket/udpsocket.c	(revision 36037)
+++ ext/socket/udpsocket.c	(working copy)
@@ -112,6 +112,7 @@ udp_connect(VALUE sock, VALUE host, VALU
 static VALUE
 udp_bind(VALUE sock, VALUE host, VALUE port)
 {
+    VALUE mesg;
     rb_io_t *fptr;
     struct addrinfo *res0, *res;
 
@@ -126,7 +127,13 @@ udp_bind(VALUE sock, VALUE host, VALUE p
 	return INT2FIX(0);
     }
     freeaddrinfo(res0);
-    rb_sys_fail("bind(2)");
+
+    port = rb_String(port);
+    mesg = rb_sprintf("bind(2) for \"%s\" port %s",
+	StringValueCStr(host),
+	StringValueCStr(port));
+    rb_sys_fail_str(mesg);
+
     return INT2FIX(0);
 }
 
Index: ext/socket/ipsocket.c
===================================================================
--- ext/socket/ipsocket.c	(revision 36037)
+++ ext/socket/ipsocket.c	(working copy)
@@ -43,7 +43,7 @@ init_inetsock_internal(struct inetsock_a
 {
     int type = arg->type;
     struct addrinfo *res;
-    int fd, status = 0;
+    int fd, status = 0, local = 0;
     const char *syscall = 0;
 
     arg->remote.res = rsock_addrinfo(arg->remote.host, arg->remote.serv, SOCK_STREAM,
@@ -81,6 +81,7 @@ init_inetsock_internal(struct inetsock_a
 	else {
 	    if (arg->local.res) {
 		status = bind(fd, arg->local.res->ai_addr, arg->local.res->ai_addrlen);
+		local = status;
 		syscall = "bind(2)";
 	    }
 
@@ -99,7 +100,24 @@ init_inetsock_internal(struct inetsock_a
 	    break;
     }
     if (status < 0) {
-	rb_sys_fail(syscall);
+	VALUE host, port, mesg;
+	const char * local_mesg;
+
+	if (local < 0) {
+	    host = arg->local.host;
+	    port = rb_String(arg->local.serv);
+	    local_mesg = " (local address)";
+	} else {
+	    host = arg->remote.host;
+	    port = rb_String(arg->remote.serv);
+	    local_mesg = "";
+	}
+
+	mesg = rb_sprintf("%s for \"%s\" port %s%s",
+	    syscall, StringValuePtr(host), StringValuePtr(port),
+	    local_mesg);
+
+	rb_sys_fail_str(mesg);
     }
 
     arg->fd = -1;
Index: ext/socket/socket.c
===================================================================
--- ext/socket/socket.c	(revision 36037)
+++ ext/socket/socket.c	(working copy)
@@ -10,6 +10,8 @@
 
 #include "rubysocket.h"
 
+static VALUE sock_s_unpack_sockaddr_in(VALUE, VALUE);
+
 static void
 setup_domain_and_type(VALUE domain, int *dv, VALUE type, int *tv)
 {
@@ -467,8 +469,14 @@ sock_bind(VALUE sock, VALUE addr)
 
     SockAddrStringValue(addr);
     GetOpenFile(sock, fptr);
-    if (bind(fptr->fd, (struct sockaddr*)RSTRING_PTR(addr), RSTRING_LENINT(addr)) < 0)
-	rb_sys_fail("bind(2)");
+    if (bind(fptr->fd, (struct sockaddr*)RSTRING_PTR(addr), RSTRING_LENINT(addr)) < 0) {
+	VALUE host_port = sock_s_unpack_sockaddr_in(sock, addr);
+	VALUE mesg = rb_sprintf("bind(2) for \"%s\" port %d",
+	    StringValueCStr(RARRAY_PTR(host_port)[1]),
+	    NUM2INT(RARRAY_PTR(host_port)[0]));
+
+	rb_sys_fail_str(mesg);
+    }
 
     return INT2FIX(0);
 }
Index: test/socket/test_tcp.rb
===================================================================
--- test/socket/test_tcp.rb	(revision 36037)
+++ test/socket/test_tcp.rb	(working copy)
@@ -6,6 +6,23 @@ end
 
 
 class TestSocket_TCPSocket < Test::Unit::TestCase
+  def test_initialize_failure
+    s = TCPServer.new("localhost", nil)
+    server_port = s.addr[1]
+
+    c = TCPSocket.new("localhost", server_port)
+    client_port = c.addr[1]
+
+    begin
+      # TCPServer.new uses SO_REUSEADDR so we must create a failure on the
+      # local address.
+      TCPSocket.new("localhost", server_port, "localhost", client_port)
+      flunk "expected SystemCallError"
+    rescue SystemCallError => e
+      assert_match "for \"localhost\" port #{client_port}", e.message
+    end
+  end
+
   def test_recvfrom
     svr = TCPServer.new("localhost", 0)
     th = Thread.new {
Index: test/socket/test_socket.rb
===================================================================
--- test/socket/test_socket.rb	(revision 36037)
+++ test/socket/test_socket.rb	(working copy)
@@ -70,6 +70,22 @@ class TestSocket < Test::Unit::TestCase
     }
   end
 
+  def test_bind
+    Socket.open(Socket::AF_INET, Socket::SOCK_STREAM, 0) {|bound|
+      bound.bind(Socket.sockaddr_in(0, "127.0.0.1"))
+      addr = bound.getsockname
+      port, = Socket.unpack_sockaddr_in(addr)
+
+      Socket.open(Socket::AF_INET, Socket::SOCK_STREAM, 0) {|s|
+        e = assert_raises(Errno::EADDRINUSE) do
+          s.bind(Socket.sockaddr_in(port, "127.0.0.1"))
+        end
+
+        assert_match "bind(2) for \"127.0.0.1\" port #{port}", e.message
+      }
+    }
+  end
+
   def test_getaddrinfo
     # This should not send a DNS query because AF_UNIX.
     assert_raise(SocketError) { Socket.getaddrinfo("www.kame.net", 80, "AF_UNIX") }
Index: test/socket/test_udp.rb
===================================================================
--- test/socket/test_udp.rb	(revision 36037)
+++ test/socket/test_udp.rb	(working copy)
@@ -36,4 +36,20 @@ class TestSocket_UDPSocket < Test::Unit:
       s.bind(host, 2000)
     }
   end
+
+  def test_bind_addrinuse
+    host = "127.0.0.1"
+    port = 2001
+
+    in_use = UDPSocket.new
+    in_use.bind(host, port)
+
+    s = UDPSocket.new
+    
+    e = assert_raises(Errno::EADDRINUSE) do
+      s.bind(host, port)
+    end
+
+    assert_match "bind(2) for \"#{host}\" port #{port}", e.message
+  end
 end if defined?(UDPSocket)