The only solution I have found it to be in HTML mode instead of Visual when creating a link.
I think Apple broke Safari this past week with the updates they pushed across for all their applications. Many folks are experiencing this and have posted on Apple’s forums.
Use Firefox in the meantime.
I can confirm that Safari, v3.03 (522.12.1), is still having issues with WordPress v2.3 editor.
I also must say that the latest set of upgrades Apple pushed across the pipe this past week has broken my Safari and many other people’s Safari browsers into being a slow, unusable application.
The solution is to use Firefox until Apple can get things sorted out.
