Is there an easy way to flour a tube pan?

I second the recommenation of Baker's Joy (or Pam for Baking, a similar product that seems to be more widely available in supermarkets). My cooking style is pretty Old School--I'm skeptical of convenience products and prefer not to use aerosol sprays. But Baker's Joy definitely saves time and prevents failure from inadequately floured pans.

Thanks, all, for the good advice. Before I look for Baker's Joy, I'll try mimicking a shaker with a small mesh sieve that I have, and tapping the flour over the greased tube. This will, no doubt, improve my present situation of covering everything, except for the tube, in flour. Myself included.

A shaker with flour in it works really well for this, but it is, no matter how you do it, somewhat awkward. Just be prepared to tip and bang and rotate, then shake a bit more in to the bare spots and tip and tap and tilt and shake the pan until it's fully covered. And don't worry much about not getting every last spot floured. The cake will be fine with a few small bare spots here and there, especially if you've sprayed it down well with the oil. ;o)

This isn't very helpful to you at the moment, I'm sure, but I find those grease sprays with flour in them to be amazingly helpful. The aptly named "Baker's Joy" is a good one, Pam and various store versions also make products like this.

For your current predicament though, scooping some flour in and tapping the thing as you rotate it around (preferably over your flour container, to catch the fallout) is as good as I've ever been able to do.
I will note that I've found there to be an amount of flour past which it actually becomes less effective. If I put in as much as a quarter cup at a time, it seems to clump up/not stick to the pan as well. Instead I'll do a couple of tablespoons at a time, and perhaps have to do that 2 or three times for good coverage.

It's slow and painstaking, and maybe someone else has a better solution, but not being great at this is why I've become such a fan of those sprays.

Assuming you're greasing & flouring the pan, a spray coat should get in the nooks and crannies. To dust the pan with flour after, put as much as you think it needs in the pan and shake the excess around, tilting the pan as needed to coat all surfaces. Do this over a tray to catch spills and tip back in if need be. Tap out any excess.