Need a macro to search for a character in a cell, then delete all text prior to it.

I have a spreadsheet with Outlook logs that I need to sort by date. Unfortunately, the entries are text and appear as follows:
6/28/2010 2:01:30 PM (2010-06-28 18:01:30 UTC)

I want to be able to delete all the text from the open parenthesis back to the beginning of the cell. Obviously I can do it manually for each cell, but there are about 3000 entries, so that isn't practical.

Assuming the following can be done, what I'd like to do is create a macro that looks for the open parenthesis, moves the insertion point to the right of it, selects all the text from that point back to the beginning of the cell, and then deletes it.

That would leave the text so that the year of the entry is first, and I can accurately sort it even if it remains formatted as text.

Unfortunately, I haven't been able to figure out how to get this done. The search function seems to work only to find a particular cell, not to search and create an insert within a cell. Any help would be greatly appreciated.