A plan is afoot, and has been for several years, for a major new museum in the United Kingdom. While the UK does have an abundance of museums, it lacks one devoted to the importance of migration to these islands. According to the proposal (here, PDF) the Migration Museum would "treat immigration as a major event," use interactive story techniques, discuss migration into and out of the UK, and include exhibits and a research archive.
Further information about the proposed museum is included in a 2009 discussion paper (here, PDF) by ippr (the Institute for Policy Research). They argue that the museum would benefit the citizens of the UK by highlighting their shared history which would help establish a shared sense of identity. They also propose creating a database of researchers working on migration history (see item 6 on pg. 12).
The third piece of literature regarding the museum is the 2009 report, "Stories Old and New: Migration and Identity in the UK Heritage Sector" by Mary Stevens. This report is essentially a literature review of what already about exists in the UK regarding migration. Basically, there isn't much as unlike the US and Australia the UK has never defined itself as a nation of immigrants; it simply isn't part of the national narrative. The report further addresses how the heritage sector can play a role in changing the narrative. While this report clearly focuses on migration into the UK, it does mention a several resources on emigration, for example the The Swedish House of Emigrants (aka The Swedish Emigrant Institute).
While the Migration Museum is still in the project stage it does have a website (here) where you can learn more about the project, find a Learning Zone with teaching resources, view the 100 Images of Migration Gallery, and more. Keep up to date with the Museum via Twitter (@MigrationUK).
Look for future posts on selected emigration resources mentioned in the report.