Yes, we can celebrate Eid-e-Miladunnabi (sallallahu alaihi wasallam). Since any kind of good news is allowed in islam to be celebrate, therefore the Birth of Prophet Muhammad (Sallallahu alaihi wasallam) is the most happiest news and occasion for every muslim. That is why celebrating this Holy day is permissible in Islam. Further it is no where in the Quran or Hadith prohibited to celebrate this day and according to the Islamic rulings, those things which are not restricted by any instruction from ALLAH (azzawajal) and Prophet Muhammad sallallahu alaihi wasallam) is permissible.

These were few general points on support of celebrating Eid-e-Miladunnabi sallallahu alaihi wasallam. There are several more evidence that could be derived from Holy Quran and Hadith which authenticates the permissebility of celebrating this Holy day. Please don't hesitate to ask further queries regarding this matter. Wallahu alam O Rasuluhu