Yes and no. The Omega Man was based on the book "I am Legend" and , not surprisingly, so is this new movie. There are considerable differences, however.
The origin of the virus was different in both movies, but that doesn't make a dime's bit of difference to the plot. The major difference between the two movies is in the portrayal of the infected.
In The Omega Man, the infected build a new society which is very cult-like and they have what I could only describe as a religious hatred for all things technological. They have a charismatic leader (played by Anthony Zerb) who is a powerful nemesis to Charlton Heston's character.
In the new movie, the infected have lost all of their humanity and are more like animals. They are unrealistically fast and strong, and also sport unrealistically wide opening mouths. They are just mean and nasty like packs of vicious animals.
I don't know which is more like the book, since I never read it, but I think that The Omega Man was more engaging. That is not to say that I Am Legend is bad. It's still pretty good, but The Omega Man rules.
Omega Man was quite the movie in it’s day.
It’s even become a bit of the vernacular in my age group (late boomers)....”an Omega Man lanscape”
Omega Man was very like the book, in that at the end the "new men" will go on and create a new society, with Heston as the dark daemon of their new legends (hence the title "I am Legend", which is the last line of the book as the hero realizes all this)
If the new movie has the infected being mindless animals, then it diverges greatly from the book
It's great to see it blow Golden Compass away
The movie with Vincent Price is most true to the book. You can watch it in entirety on youtube.