I use the wonderful gallery to host my photos.
Every so often I upgrade it or perform some sort of maintenance on it. And everytime I have to search for a particular link that tells me how to configure the software so that I can view it from inside my LAN and from the Internet. I want to preserve the linkso I don't lose it again!
It's item C.22 of the FAQ.
I do recommend the software though ngallery and coppermine look quite good too.
What do you use to host your photos (and BTW I'm not interested in any online facility, flickr is great and all but I want to host them on my own PC thanks very much)? :)