when using firefox 3, it seems that links generated using the rich text editor (rte) get prefixed like this: http://typo3/http://[target]

this happens only with firefox 3, as far as known. the cheapest workaround would be using a different web browser when working with typo3.
a not so cheap workaround would be to switch off the rte after setting the links and correct the linkage in the html code.

see also the german hint at http://www.zechendorf.com/