Research from the Juniper Networks has found that malware aimed specifically towards Android-running devices has increased 472% since this past summer.  Wow.

You really need to be careful what you download and install these days.  If you don’t have a system password or another method of protecting your phone, you should really look into it. The malware in question is mostly designed to steal personal information.  Be very careful of what you install.

PC World has written a very neat article discussing the points of interest between a closed vs open maketplace.  I would encourage you to check that out here.