How do I report these comments?Blogger has told us that the new comment moderation system is not yet rolled out to all blogs, as this is being done on a blog by blog basis.
If you don't yet see a "Mark as spam" link or selection in your comment moderation queue, rest assured that you will, soon. And later, you'll stop seeing the typical "Nice blog" spam - unless you go diving into the Spam Comments folder.
Be patient, your blog will have the new system shortly - if it does not, already. And if your blog does offer you this ability, use it. The new system depends upon your input - it will not know what should be put into Spam directly, without votes from you and others like you. And remember to use it frequently, and promptly, for best results.
(Update 8/17): A discussion today suggests that some blogs may not be getting the new commenting system, if comment moderation is disabled. If you are waiting for the new system, and your blog does not use moderation (possibly intentionally), enable moderation. Select "Only on posts older than" and give it 90 , 180, or 365 days. That will give you unmoderated posts, for anything but very old posts, and possibly give you the new system.