Can I re-install a purchased app from Google's Play Store? I've successfully purchased an app from the Market via my Android phone. It's currently too large for my internal memory (still running 2.1), so can I uninstall it and then re-install it at a later time?

Will uninstalling the app (after the 15 minute eval period elapses), also ensure that I can't re-download it again or do purchased apps remain linked to my Google account even if they aren't currently installed?
You can uninstall it and the market will remember that you bought it.  It'll say "purchased" in the market and you can reinstall any time. Every time I reflash a ROM I go into my downloads section of the market and I see all my purchased apps.