One more data formatting question

Hi all: I'm trying to parse out some HTML code back into "regular" string values and I keep getting tripped up by the non-breaking space value ( ). I see that html_decode_entities() can be used to convert this back to a viewable space, but the documentation tells me that the space value it uses is not the same as a TRIMable space (i.e., ASCII 32). Is there a quick, fast, and easily implemented way to convert any non-breaking space found in a string back to the ASCII 32 space value? I suspect that one of those amazing POSIX expressions could do it, but I'm having trouble wrapping my head around them at this early hour. Any help you all can provide will be extremely appreciated! Thanks, Jon