That says it all in the subject line ...

in ASP

Code:
myNewString = replace(myOldString,"_"," ")
Would replace all instances of "_" found in myOldString with " ".

Can this also be done in PHP?

PS - I do have a PHP book, just not a very good one, and I am a total beginner with PHP (very stuck in my ASP/VBscript ways, but I want to change!)