I upgraded my MacBook to Leopard.
It feels slower and wireless is broken. Gee. Thanks Apple!
It seems the issue with wireless is well known - still no solution from Apple as yet. So, when I switch it on, I have to use Assist to get my wireless up and running. Tedious.
UPDATE: Seems rebooting the router helped, along with clearing out the keys. Also mail was broken but deleting the configuration helped there too.