Poderosa's tabs are more like panes of the same window. Fortunately you don't lose the info from your configuration files ('tleast I don't). WinTabber looks like it brings the supported terminal emulators closer to the Firefox, OS X Preferences kind of Tabs.
(On that, does anyone know if it has support for rxvt? I didn't see anything on the product page about it.)

Vernon's blog: Tabbed terminal under Cygwin using mrxvt tabs

Some people have issues with how much, what kind, how new the stuff in their X11 installs are for Cygwin, as you'll see in the comments. But if you, like me, have been cruising around the Web trying out this and that solution, terminal, low-profile X11 app and finding different things out about each one, you ought to have whatever's necessary to install MRXVT according to Vernon's instructions without a hitch or hiccup.

Personal note: it's also the first time I was able to launch XWin from my Cygwin rxvt without it arguing with me about who owned my screen. Turns out if you get behind both with a call to put up X apps by way of your machine's ip (and localhost: won't do it, either, I'm guessing), it works like a charm.

BZT

I'd suggest screen. It's not graphical tabbing, but it works even without X11 installed, and keeps your programs running even when you log out. Plus, you don't have to install it on every PC you're using to login since it runs on the server.

Re: Screen - Do you have its full name or a link from which to download it?

Full name: GNU screen
Where to get it:

• Debian/[Xu|Ku|U]buntu: apt-get install screen
• SuSE: zypper install screen
• Gentoo: emerge screen
• RedHat/Fedora: yum install screen
• Windows: Available via Cygwin

And I just found another one. Standalone, like Poderosa and WinTab, multi-platform (OS X and a few Linuxes like Ubuntu, Fedora & Solaris), tabs in the more familiar Web-browser fashion, and free under GNU GPL.

The Windows version does require Cygwin with Ruby, however, which puts it a little further down my 'hassle-free install' list so far as standalone emulators go. I mean, presently I have both installed, but in the future it may be different.

Just one more vegetable to add to the stew .

BZT

Read and download here