I first saw a scan of the stamp on the right on a stamp website and told myself that I just had to have that stamp. Luckily, I have a friend in Malaysia who still had a set to spare and he was able to send me this neat cover.
It turns out the these stamps make up a 2v issue entitled 46th Independence Celebration, released 19 Aug 2003. The inscription at the bottom of both stamps reads "Sambutan Ulangtahun Kemerdekaan Ke-46/ 46th Independence Celebration" and the inscription on the right of the 30-sen stamp (depicting the large flag on the 95-meter flagpole at Merdeka Square in KL) reads "Kibarkan Bendera Kita / Raise Our Flag." The cover was postmarked at Pusat Mel Bukit Raja, Selangor, on 02 Feb 2008.
An interesting thing to note is that the word for flag in Filipino is "Bandera," which is borrowed from the Spanish language; in Bahasa Melayu, it seems to be "Bendera" and I find the similarity quite striking as Malaysia was never colonized by the Spanish like the Philippines was... or maybe the similarity is just a freak coincidence? But I did read on Wikipedia that "There are also Eurasians of mixed Filipino and Spanish descent [in Malaysia], mostly in Sabah. Descended from immigrants from the Philippines, some speak Chavacano, the only Spanish-based Creole language in Asia."
Follow-up on this:
I consulted a Malay dictionary today and looked up "bendera." It seems that the word is of Portuguese origin and so that probably explains the resemblance to Filipino "bandera." An interesting thing to note is that "bendera" is defined as: "a flag (of European type)." I guess the Malays had a different concept of how a flag looked?