In addition to the well publicized Google Glass there are a couple of interesting kickstarter projects in this space. Memento is the most mature as far as I know but ParaShoot appeared recently and has some promising features, like all day battery by incorporating it into the neckstrap and wireless transmission to overcome the painful charge/sync cycle on the Microsoft SenseCam (Vicon Revue, now discontinued).
I often get asked about the legality of wearing a lifelogging camera. For this I turn to photographers who have been looking at the issue of taking still images in public and private places for a long time. There is a comprehensive country by country guide and for those interested in the UK situation there is a very comprehensive site (and another with a handy 2-page printable PDF) but the short version for the UK is that in a public place where there is no normal expectation of privacy you can take photos of anything unless you are actively harassing someone. This means that you can stand on public land and take images of private property. While on private property you should follow whatever rules the owner insists on and they have the right to ask you to leave, but you don’t have to delete any images you may have already taken. In general no one can delete your images without permission and the police can only seize your or memory cards in the context of arresting you for an offence (most of the time taking images isn’t an offense).