[sdiy] weller soldering tip

[Tom FitzGibbon]

Hello All,
thanks for all the tips about stripboard, schematics, etc. 
all your info will come in handy down the road.
Now, on to a new question
I have a 20 watt weller soldering iron (orange model)
and the tip is nearly burnt to a crisp. I cant find one locally 
and I am having trouble getting one online because i dont know the
model number of what im looking for...
any tips?
also- 
what are the advantages of upgrading to a regulated power soldering station?
thanks
-Tom