0001057352-08-000044 10-Q 5 20080331 20080509 20080508 COSTAR GROUP INC 0001057352 7389 522091509 1231 10-Q 34 000-24531 08815702 2 BETHESDA METRO CENTER 10TH FLOOR BETHESDA MD 20814 3012158300 2 BETHESDA METRO CENTER 10TH FLOOR BETHESDA MD 20814 10-Q 1 first_quarter200810-q.htm 1Q 2008 REPORT EX-31.1 2 exhibit31_1.htm SEC CEO CERT EX-31.2 3 exhibit31_2.htm SEC CFO CERT EX-32.1 4 exhibit32_1.htm SEC CEO 906 CERT EX-32.2 5 exhibit32_2.htm SEC CFO 906 CERT