Are two indexes needed?
An index can seek by a subset of characters, as long as you're searching from the left.  E.g., "Inter%" can seek, "%net" will not.

However, the first character is not necessarily the character under which the article would be sorted.  "The Internet" should go under "I", not "T".  You probably need two fields, DisplayTitle and SortTitle; a single-character index on the latter may be worthwhile, but most likely a full-length index will be just fine.

Indexes are typically B-trees, and a seek will jump to the right location about equally quickly whether you have 10 or 100 entries per page.  Scans are another matter, but I'd start with the simplest solution and add an extra index only if performance proves inadequate in practice.