Passing Strings from VB to Delphi DLL, HELP!

Hi All,
Could anyone give me an idea on How I pass a string from VB to a
delphi DLL and back again, all I know is that I have to pass it Byref
from the VB side, and maybe(?) pick it up as an array on the delphi
side. Other Than this I'm banging my head against a wall the help is
useless, and I have no manuals( I'm using a demo copy)
Any help would be greatly appreciated

Many thanks
John