It would be awesome if PHP had the strip_accents() function. Something like strip_tags(), only it removes the accented letters and replace them with their non-accented version. 

For example: 
<? echo strip_accents("Bonjour V?ronique, comment ?a va?") ?>
gives: Bonjour Veronique, comment ca va?

I suppose it would be even better if you could have an optional parameter of allowable accents too.

It would be very useful for searching databases.
For example: on my site, people can search a music band database, but if they don't have the umlauts on their keyboards, and if they search for a band like say "M?tley Cr?e" without typing the umlauts they might not find it. So I have to use an alternate spelling field, but it would be awesome if there were a built-in strip_accents() function. I'm sure it could have many many more applications too :)