Hello there,
I was wondering if it is legal and acceptable to use a well known typeface such as Arial or Georgia for example and 're-create' it to make it look different..such as looking 'dirty' and 'grungey' ?

Edit// I just found this: http://www.dafont.com/times-new-yorker.font So it is possible, yes?

If 'possible' means 'doable' ...

For a "private use", probably yes.
For a "public use", probably no. Perhaps it can be beser for you to choice a basic font not so famous than Arial, created by no-professional, and contact him to agree what's possible.

You wouldn't be the first one to do it!

http://www.dafont.com/gastada.font
http://www.dafont.com/impacted.font
http://www.dafont.com/decade.font
http://www.dafont.com/raven.font
http://www.dafont.com/romeo.font
http://www.dafont.com/soopafresh.font
http://www.dafont.com/you-are-loved.font
...

Thanks for the replies!

heh, that Impacted font guy/gal didn't even try to modify the alternate characters.