Hi not necessarily Linux specific this one, but wouldn't it be a good idea for Skype to automatically strip out brackets and anything in the brackets from phone numbers that are pasted into the number box.
Here in the UK at least when people internationalise their numbers they write them like this:

+44 (0) 207 12345678

If Skype stripped out the brackets then I could simply paste any of my internatiomnalised numbers into skype without having to manually remove the brackets.
This would also be handy for callto:// handling.
A more advanced version of this idea would allow you to set a default country such as the UK ( +44 or 0044 ) and for every number entered that did not begin with 00 or + Skype would assume +44 etc and strip the first zero.
Again this would mean that all the numbers I had access to either in my address book or via calltoo:// that are not International would just work.

Mat