Have you been paying attention? The House leadership only knew about some innocuous, though annoying e-mails from several years ago. There was nothing about them to cause Foley to resign. These IMs that were actually sexually explicit were from three years ago, but the House leadership did NOT know about them until they were announced by the press last week. When those were made public, I think the House leaders had a sit down with Mr. Foley, after which Foley resigned.
Don't go blaming the Republicans for this because you'll be falling right into the trap the Democrats want. They fed this story to ABC, which printed it, purposely blurring the lines between the e-mails and IMs so that people would blame the Republican leaders for allowing this man to stay in his office. It WASN'T the Republicans who had the IMs, but someone did. Hastert has started the ball rolling to find out exactly WHO had them and gave them to ABC.
OR
Was it simply copied and pasted into a document or email and sent off to someone?...Who was it sent to?...and how did it eventually get to ABC?