Finland is the promised land of music festivals, and there are a lot of happenings throughout the year. Finland Festivals lists all the noteworthy happenings, but below you get the direct links to all available homepages:

Lahti Organ Festival
Naantali Music Festival
Savonlinna Opera Festival
Tampere Biennale
Crusell-week
Turku Music Festival

We have here a general view of Finnish classical Orchestras. Below are the homepages available at this moment:

Finnish Radio Symphony Orchestra
National Opera Orchestra
Helsinki Philharmonic Orchestra
Avanti! chamber orchestra
Tampere Philharmonic Orchestra
Turku Philharmonic Orchestra
Sinfonia Lahti
Tapiola Sinfonietta
Finnish Chamber Orchestra
Symphony Orchestra VIVO
Ylioppilaskunnan Soittajat - YS
Baroque Orchestra & Ensemble Opus X

Best resource for Finnish composer and work info is the Finnish Music Information Centre.

Finnish artists are scattered around the net, some on record company pages, some have their own homepages:

Anssi Mattila
Jukka-Pekka Saraste
Sakari Oramo
Leif Segerstam speaks
Arto Wikla (lute)

Further reading about finnish musicians and artists is offered by VIRTUAL FINLAND, a wonderful resource of Finnish life and culture, maintained by Finnish Foreign Ministry. They have info about:

Jukka-Pekka Saraste ··· Esa-Pekka Salonen ··· Aulis Sallinen ··· Jorma Hynninen ··· Kaija Saariaho ··· Karita Mattila ··· Magnus Lindberg ··· Matti Salminen ··· Monica Groop ··· Olli Mustonen ··· Ralf Gothóni ··· Paavo Berglund ··· Jean Sibelius

You'll find the essential info about extremely virile finnish choir culture in "Choral Finland Homepage" There you'll find pages about finnish choirs, choir organizations, choir composers, history of choirs in Finland, publishers, concerts, etc. Choral Finland pages are maintained by Sulasol (The Finnish Amateur Musicians' Association).

Sibelius-Academy choir links
Tapiola Choir
Tapiola Chamber Choir
Tampere Philharmonic Choir
The Helsinki University Chorus
The Polytech Choir