well, i read the documentation, but it doesn't really say how to do the upgrade for v4.x, probably because there was only 1 version of v4.x when the doc was semi-updated.  though the process may not have changed, the folder structures between the 2 versions v3.x and v4.x are different, so it would help people to update the doc or post some 'official instructions' related to dnn v4.x specifically.  the existing doc is confusing lumping all mention of dnnv4.x to references to dnn3.x instructions.  if you are starting new with dnnv4.x, the doc doesn't do much good at clarifying the process.

here's what i did to upgrade on my test box, running sql2005, asp.net v2.x, winxp pro, and dnn v4.0.2

1. backup the existing folder pointed to by my virtual dnn v4.0.2 site.
2. backup my db in sqlv2005
3. downloaded the new beta version
4. extracted files to the folder pointed to by my dnn v4.0.2 stie, rembering to use the option use foldernames, and overwriting the files.
5. checked the web.config to ensure that that the previous machine codes and db connection strings were untouched, which they were! So, did not need to do anything else.
6. browsed to the site, letting the auto update complete.
7. the site came up with the new version operational, the v4.0.3 name in the browser showed, so i'm good to go.

this worked for me, and it is not the 'official' way to do it, and if you have any source modified, you'll want to make sure you put it back in the new folders locations where needed, and recompile to pickup your mods again.  so, just be careful, but no broken db or server was experienced by me.

oh, and you're welcome...