I've posted about this before in previous HN stories, but it's actually not that dodgy: because EU borders are open (you can move between EU countries freely) it's important to have a process for arrest warrants that are valid throughout the EU.
That's what's happened here: Sweden wants to question Assange, with a view to potentially bringing charges. They have issued an arrest warrant to arrest him - his guilt is irrelevant.
As many people have mentioned, the UK actually has a strong record of extraditing people to the US: if anything, Sweden is less co-operative (for example, Roman Polanski will never set foot in the UK for fear of being arrested and extradited, but he was happy to enter Sweden).
That's what's happened here: Sweden wants to question Assange, with a view to potentially bringing charges. They have issued an arrest warrant to arrest him - his guilt is irrelevant.
As many people have mentioned, the UK actually has a strong record of extraditing people to the US: if anything, Sweden is less co-operative (for example, Roman Polanski will never set foot in the UK for fear of being arrested and extradited, but he was happy to enter Sweden).