Lexis-Nexis Quicklaw offers email alerts based on searches that you create. Additionally, any search may be saved and then re-run at specified intervals with the results emailed to the user.
Netletters provides summaries of relevant new cases with links to the full text.
WestlawCanada offers search-based email alerts and also offers a Business Practitioner collection of resources available through the "add a tab" function. This collection is US-focused, but contains resources with international relevance.