I am surprised and disappointed by the results. I have always accepted (and informed my students) that I have been to is an odd form, and that it is used in a way that has as much to do with going (or coming) and returning as with being, but I have always considered been as the past participle of BE, not of GO.
As nobody has yet explained how been is a past participle of GO - they have merely asserted this - my own belief is unchanged. I shall, however, no longer boldly claim that people who hold the other belief are out of line with current teaching. I shall content myself with knowing in my own mind that they are misguided.
As far as I am concerned, this marks the end of my participation in this thread, though I shall follow it in case anybody comes up with any startling new information. It's been interesting - for me at least.
You may want to read Why Go Doesn't Have Two Past Participles by Joseph Hilferty. There's a pdf version of the paper available on-line.
I heard some other 'jokes' like that:
"Had to" is the past form of "must"
"Smaller" is the form of " little"
"We" is the plural form of "I", etc.
Most of the people saying such things aren't linguists but English teachers trying to make it easy for their students to understand grammar rules.
Because the Present Perfect focuses on events that happen before now, it is possible to perceive events from two different perspectives, before and now, as shown by the ambiguity inherent here:
[1a] Juan has gone fishing = He is not here now.
[1b] Juan has gone fishing = He has done it before.
[2a] Juan has gone to London = He is not here now.
[2b] Juan has gone to London = He has visited London before.
[3a] Juan has gone to school = He is not here now.
[3b] Juan has gone to school = He has attended school before.
The meanings expressed in the [a] examples are what we expect from a traditional standpoint, and whether or not the [b] examples (what appear to be a modern twist on the interpretation of the Present Perfect) are near-synonymous with the meaning expressed by has been (experienced something) depends on the Modern Day speaker, which is why you'll find that answers to the question, Is been the past participle of Go? are inconsistent.
As for me, been and gone are not synonymous, but that's just me. To me, been is the past participle of Be, not Go;i.e., I have been to London before means, to me, I have experienced London before (there's a Be verb there, not a Go verb), whereas I have gone to London before sounds awkward to me because gone means haven't returned yet, but I know what speakers mean when they use gone for been and I neither mind, nor care (but traditionalist care). I adapt; it's what speakers do.