Just to clarify what Shaykh Yasir Qadhi actually said on this issue (which I personally found very balanced):
Akhi, seriously we need to pause for a while and ask ourselves: what exactly are these people trying to prove? Can any sane Muslim seriously try to legitamize directly asking the Prophet salla Allahu alayhi wa sallam for something that only Allah should be asked of? Matters like life and death, sustenence, forgiveness, cures, etc... Is this was the Quran tells us to do? Is this why the beloved Rasool was sent: so that HE be taken as an object of worship besides Allah?
If any person openly proclaims such beleifs, then he has contradicted numerous explicit verses in the Quran, and there is no serious need to show his deviancy. He has placed himself to a level similar to some groups of the Christians.
All of this needs to be taken into perspective... to say 'Ya Muhammad' does not entail any of the above. There are various types of nidaa (calling out), one of which is to recall the person whom you mention.
Numerous are the verses of pre-Islamic poetry in which the poet addresses his beloved; this does not imply that he is beseaching her or making du'aa to her! It is only that he is recalling and remembering her to such a level that it is as if she is in front of him. Again this is an issue which all linguists agree upon - just look up any book of Arabic grammer under the chapter of Nidaa.
Also, note how Ahl al-Bid'a seek to use vague or inauthetnic hadeeths, which they pick and choose selectively from a wide array of sources (for example, al-Mu'jam al-Kabeer of at-Tabarani is by no stretch of the imagination one of the primary sources of our religion, with all due respect fo course to the great scholar of hadeeth who compiled it), and yet they ignore explicit verses in the Quran, and authentic ahadeeth in the Saheehayn!! Who was it who said, "Do not take my grave as a place of regular visitation, and send salaat upon me wherever you are, for it reaches me..."? Notice, he is in fact stating that we should not regularly visit his grave to say salaam to him, much less make du'aa!! (Again, the prohibition is on FREQUENT visitation, and not the actual visitation). Who was it that said, "Allah's curse is on the Jews and Christians because they took the graves of their prophets as places of worship?" And this is in regards to worshipping ALLAH at these location, how much more the evil when the grave itself becomes the object of worship?!
Really, there is no need to quote obscure scholars for such blatant shirk: ask this person what exactly is he trying to prove. Is he stating that we can make du'aa to the Rasool and ask him to forgive our sins? If he is, then he should support the Christians in their claims to be people of Paradise, for his actions are no different from theirs.
Or is he trying to prove the high rank and status of our Rasool, and the many blessings he has been given? If it is the latter, then this is something we all agree with, and has nothing to do with directing acts of worship to him.
The hadeeth about 'calling out to the servants of Allah' when one is lost is also weak; again this can easily be shown. But even if one is not aware of this ruling, you simply need to ask yourself: is this what our religion is about? Is this the meaning of la ilaah illa Allah...that we direct our du'aas, love, fear, hope, and acts of worship to all of the creation besides Allah? Once a person understands the essence of Islam, the meaning of the kalimah, and the shirk of the Jahiliyyah Arabs, everything will be put in place. All of these 'evidences' that are brought forth simply cannot hold up against the entire message of the Quran. Remember that Allah mentions in the Quran itself that some of its verses are of ambiguous meaning, and those who have a disease in their hearts will try to use these verses in order to prove their falsehood. If this is the case with the Speach of Allah itself, how much more so when we are dealing with ahadeeth whose authenticity might be difficult for the average layman to verify?
Always go back to the clear verses in the Quran and the ahadeeth that are in the famous works of Islam, and don't allow one obscure text to contradict the very gist of our religion.