What are you trying to do exactly?
If you're just importing ss2 textures into UnrealEd, it's really pretty simple... just import pcx's into a texture package.
Or are you trying to do maps as well? Ages ago, Datoyminatah wrote a perl script that converted thief/ss2 maps into unrealed readable format. It's old, but there's a thread about it somewhere in the Thievery mapping forum.
Re copyright, because of copyright fascism laws bought by large corporations and sustained by some peoples naive belief in bourgeois ideology, EA can ask you to remove any downloads you put up or else they can sue you. But they probably won't care as long as you're not doing anything commercial or explicitly anti-capitalist.
Mind: those high res textures that people were doing for replacing existing ss2 textures might be a totally different matter.