which opera do i need for 800 and how can i install it?

Opera was available in OS2007 and was integrated in the OS. OS2008 doesn't have any Opera and you can't install it.

Why do you need Opera for the N800 when it comes with microB built-in?

It is faster?

Opera is generally a faster browser.
Also, the "right click" function (hold the stylus on a link to obtain an options menu) works ALL the time in Opera, but it doesn't work much of the time with microB. I use this feature often in order to open a link in a new window (a substitute for tabbed browsing.)
Some sites will render better in microB, such as Google Docs. You can always "switch engines" and use microB to view these sites.
I'm still using OS2007 on my N800 and I have no intention of changing.

Mmm . . . it's fun being stuck in the past.

So if the past works for you, you should still upgrade, even though it may not do what you want?

10x everyone! i love opera on my pc thats why i asked about it. Happy Easter!

has anyone managed to port opera to os2007/n810 yet? as im really getting annooyed with mozilla/microb thing, it cant cope with google mail and google docs open at the same time at any speed.

edit;
argh i cant use the thread links in microb to subscribe as hover menus dont work

Opera is closed source, so we couldn't "port" it. (Should just be a recompile, anyway, I think).

It is possible to copy the OS2007 version, and enough OS2007 libraries, to make it work. Indeed, if you wanted to set up an OS2007 chroot, it'd probably work straight off. But chroot isn't an easy path, and installing OS2007 Opera and all dependencies would probably come close to filling the device's memory.