These are the border towns on the Swedish-Finish border. Haparanda is on the Swedish side, Tornio on the Finish side of the border. While Haparanda is mainly has two big shopping centers, while Tornio has a little town center with a few bars. But anyway, everything is in walking distance. Don't forget that they have different time zones: Finnish time is one hour ahead of Swedish time!
The Hostel Haparanda Vandrarhem is at Strandgatan 26 in Haparanda close to the border. It's a nice and clean place to stay and has open all year round. Reception is only open between 4pm and 7pm (Swedish time), phone +46-92261171. Dorm bed 180 SEK usually in a four bed dorm, single room from 250 SEK, double room from 470 SEK, bed-linen 50 SEK. So, as always in Sweden better bring your own bed-linen (sleeping bags are not allowed). If you start your trip through Sweden here and you don't have bed-linens with you, better buy a set of linen at the IKEA market in Haparanda.
The Tornio-Haparanda Tourist Office is on the Finnish side very close to the border. They have a Swedish (+46-92212010) and a Finnish (+358-16432733) phone number. The people are very helpful there. Open (Finnish time!): in summer Mon-Fri 8-19, Sat-Sun 10-18, other times Mon-Fri 10-19. On their website you can find the quite useful brochure ‘Service Guide Haparanda-Tornio’ which contains a good city map.
Even as most people speak English in Finnland, it's useful to know a few basic words and phrases in this language. For a small two-page summary of this incredible difficult language print yourself a copy of the Pocket Talk English - Finnish micro dictionary.