I've been fighting the shared folder/networking problem since the N810 was released. There are many alternative maemo apps that require an IT degree, but none is more easy to use then setting up a HTTP File Server on a windows machine and use Nokia's browser to transfer files.
I like this utility because its simple, has no installation on a windows machine (portable) and the plus side is that HFS works with any internet device regardless of OS because it uses the browser.

http://www.rejetto.com/hfs/?f=intro

I've tried and given up on OpenSSH, winscp, Wizard Mounter, root, xterm, etc, etc, etc
For those that hate command-line, but love their N810, try HFS.

Dokansshfs

winscp worked well for getting the Nokia to appear on the PC, but it seems that the biggest challange and need was getting files to the Nokia WITHOUT sitting at the PC, otherwise just use the usb cable.

With HFS, you don't even need to be at home.

Thanks for the HFS tip!

I run cygwin + openssh on my Windows box. Then, I run sshfs on my NIT, and I mount my Windows drives onto my tablet.

The trickiest bit is getting the SSH server on the Windows box.

Here's the howto I used. This one looks OK too.

sshfs can be installed from Extras and then you just need to know the right command. On the tablet, as root:

The 123.123.123.123 is of course the IP address of the server. If you have a nice name like myhomeserver.sytes.net, that will work too. The -p 2222 is the port I use to go through my home router. This lets me mount my stuff from anywhere in the world. I put my shares under MyDocs so they are visible from the OS2008 File Manager.

Apache/webdav?