Capsule for iPhone is a map app of sorts that uses your current location to let you explore places and attractions around you. You can then save the places you like or ones you'd like to remember to visit later. Since Capsule ties into Foursquare, you can even view menu information for some restaurants.
You can search Capsule by either browsing by your current location or simply searching for any place you'd like to look up more information on. It can be used as a place diary of sorts and as a discovery tool at the same time. Capsule supports tags so you can sort and find what you're looking for easier later. For example, you can create a tag for "wifi" and then when you're looking specifically for a place around you that has wifi, you can filter out the ones that don't.
All the venue and tip information you see fed into Capsule is from Foursquare. That means any restaurants or cafes that have their menus shared to Foursquare will also share them with Capsule. This makes for a nice way to only have to turn to one app for information on a restaurant, unless of course you'd like to check in.
If you would like something to help you remember what places you enjoy, the ones you didn't, and ones you want to remember to visit, Capsule is a great option with a clean interface.