bMap is jQuery plugin that allows you to quickly and easily add mapping to your website. It has been designed from the beginning to handle lots of markers, lots of layers, and custom marker icons.
The plugin can manage a sidebar for you, one with a list of markers, one with a list of layers. The sidebars can be styled with CSS. The internal Google object is exposed, so you can continue to use all of the power of the Google Maps API. You can also access the internals of the bMap object.