mp3infp.dllがいいと思います。
タグの読み取り/書き込みだけするDLLなので、解かりやすいよ。
http://win32lab.com/fsw/mp3infp/
「mp3infp.dllのみ」って書かれたのをダウンロードすればOK
以前使った時のヘッダファイルがあったんで、どうぞ。
mp3infp.as
#ifndef ___mp3infp___
#define global ___mp3infp___
#uselib "mp3infp.dll"
//DWORD mp3infp_GetVer();
#func global mp3infp_GetVer "mp3infp_GetVer"
//int mp3infp_ViewPropEx(HWND hWnd,const char *szFileName,DWORD dwPage,BOOL modeless,DWORD param1,DWORD param2);
#func global mp3infp_ViewPropEx "mp3infp_ViewPropEx" sptr,sptr,sptr,sptr,sptr,sptr
//BOOL mp3infp_ViewProp(HWND hWnd,const char *szFileName,DWORD dwPage);
#func global mp3infp_ViewProp "mp3infp_ViewProp" sptr,sptr,sptr
//DWORD mp3infp_Load(HWND hWnd,const char *szFileName);
#func global mp3infp_Load "mp3infp_Load" sptr,sptr
//DWORD mp3infp_GetType();
#func global mp3infp_GetType "mp3infp_GetType"
//BOOL mp3infp_GetValue(const char *szValueName,char **buf);
#func global mp3infp_GetValue "mp3infp_GetValue" sptr,sptr
//DWORD mp3infp_mp3_GetTagType();
#func global mp3infp_mp3_GetTagType "mp3infp_mp3_GetTagType"
//BOOL mp3infp_SetConf(char *tag,char *value);
#func global mp3infp_SetConf "mp3infp_SetConf" sptr,sptr
//DWORD mp3infp_SetValue(const char *szValueName,const char *buf);
#func global mp3infp_SetValue "mp3infp_SetValue" sptr,sptr
//DWORD mp3infp_Save(const char *szFileName);
#func global mp3infp_Save "mp3infp_Save" sptr
//DWORD mp3infp_mp3_MakeId3v1(const char *szFileName);
#func global mp3infp_mp3_MakeId3v1 "mp3infp_mp3_MakeId3v1" sptr
//DWORD mp3infp_mp3_DelId3v1(const char *szFileName);
#func global mp3infp_mp3_DelId3v1 "mp3infp_mp3_DelId3v1" sptr
//DWORD mp3infp_mp3_MakeId3v2(const char *szFileName);
#func global mp3infp_mp3_MakeId3v2 "mp3infp_mp3_MakeId3v2" sptr
//DWORD mp3infp_mp3_DelId3v2(const char *szFileName);
#func global mp3infp_mp3_DelId3v2 "mp3infp_mp3_DelId3v2" sptr
//DWORD mp3infp_mp3_MakeRMP(const char *szFileName);
#func global mp3infp_mp3_MakeRMP "mp3infp_mp3_MakeRMP" sptr
//DWORD mp3infp_mp3_DelRMP(const char *szFileName);
#func global mp3infp_mp3_DelRMP "mp3infp_mp3_DelRMP" sptr
//DWORD mp3infp_mp3_MakeApeTag(const char *szFileName);
#func global mp3infp_mp3_MakeApeTag "mp3infp_mp3_MakeApeTag" sptr
//DWORD mp3infp_mp3_DelApeTag(const char *szFileName);
#func global mp3infp_mp3_DelApeTag "mp3infp_mp3_DelApeTag" sptr
#const global MP3INFP_FILE_UNKNOWN 0x00
#const global MP3INFP_FILE_MP3 0x01
#const global MP3INFP_FILE_WAV 0x02
#const global MP3INFP_FILE_AVI 0x03
#const global MP3INFP_FILE_VQF 0x04
#const global MP3INFP_FILE_WMA 0x05
#const global MP3INFP_FILE_OGG 0x07
#const global MP3INFP_FILE_APE 0x08
#const global MP3INFP_FILE_MP4 0x09
#const global MP3INFP_HAS_MP3_ID3V1 0x00000001
#const global MP3INFP_HAS_MP3_ID3V2 0x00000002
#const global MP3INFP_HAS_MP3_RIFFSIF 0x00000004
#const global MP3INFP_HAS_MP3_ID3V1_0 0x00000008
#const global MP3INFP_HAS_MP3_ID3V1_1 0x00000010
#const global MP3INFP_HAS_MP3_ID3V2_2 0x00000020
#const global MP3INFP_HAS_MP3_ID3V2_3 0x00000040
#const global MP3INFP_HAS_MP3_ID3V2_4 0x00000080
#const global MP3INFP_HAS_MP3_APEV1 0x00000100
#const global MP3INFP_HAS_MP3_APEV2 0x00000200
#endif