Same logic applies there is no way for Salesforce to do that at this time, unless you customize something to alert you based on another criteria such as email or something. There is no way to unfront alert you if you are entering James or Jim. However there are many de-duplication programs out there such as; Data Trim and/or Ring Lead that assists with the process but typically they work off of an email address or maybe you could do Last Name and Company Name but you would have to build yourself, buy someone's else's technology or look at the free app exchange programs. There is one out there, however I found it clunky and not useful.

Our way to manage was to launch an approval process for all New Accounts and Contacts and then we de-dupe ourselves and work with the reps to the proper naming conventions, however it takes time and a great deal of administration and we only have 1,500 Accounts. We have a strict Naming Convention Policy on all New Accounts/Contacts that we train to over and over that they use Proper Names., etc. Training is key, do you use the Lead Bucket then convert, sometimes that can help as well with a proper lead conversion policy and training.

This is a sore spot for alot of users if you look on the Idea Exchange it has become very heated.