Applications on the device aren't up to much out the box, and there's not a lot of scope for improvement. However, the eagle eyed among you, with no notion of the Ovi Store (which is Nokia's attempt to overthrow the App Store and Android Market) will enter the Facebook portal and see a link to 'more applications for your 5800 XpressMusic' (we assume the phone will be recognised soon).
This leads you to a link to the Ovi Store, and means that you get access to hundreds of new applications, both free and paid for. We won't lie to you - there's not much there at the moment, as the store has yet to really get off the ground, but apparently Nokia will be integrating things like location-based offerings in the near future, meaning if you're in Italy, suddenly it will promote Italian guide and phrase books to you.
Scouring the free applications, the best we found was a strobe light/torch application - which tells you all you need to know about the quality on offer.
There's not mapping application on board sadly, which makes the GPS chip inside a little bit redundant. However, a swift online trip to Senor Google's house will have you downloading Google Maps in no time, and you'll soon be able to navigate around with ease.
Nokia also persists with a number of never to be used applications too, like Friendster and Hi5 and Boingo. Some of you will have a play with these, most of you won't, and your life won't be any the poorer for it.
The Facebook application is actually rather good though, with all the same options to poke and edit your profile as you get on the Android and iPhone versions, albeit this is through the mobile browser, rather than a standalone application.
Other applications are mostly the standard Nokia fare - ie a collection of links to popular mobile sites like Amazon or MySpace - as well as converters, GPS information and a dictionary (actually, the latter is rather good - it's a proper dictionary and everything!)