Can your try like(I tried this both in iPhone and Android rhosimulator and its works fine for me)
User.find(:all, :conditions => [ "name like '%"+name+"%'"], :select => ['name']
Note: If your model type is fixed schema then you can try like
Post.find_by_sql("SELECT * FROM 'Post' where name like '%"+name+"%'")
Have you tried the above solution?