In an unusual move for a large mainstream publishing house, Penguin UK is now open to accepting unsolicited manuscript submissions from authors for a limited time period (October 2010). The submissions most only come through to Penguin's editorial offices by email.
Details from Penguin UK below:
People frequently ask us how to go about getting published. Our company policy is to not accept unsolicited manuscripts or synopses and we cannot enter into correspondence about unpublished work. However, for a limited three-month period from the beginning of August until the end of October 2010, we will be inviting submissions to be sent in electronically to the following address: email@example.com.
Read more (Courtesy POD: Self-Publishing and Independent Publishing)