Microsoft has released Language Interface Packs for Windows 7 Beta in Microsoft Connect website. For users who do not use the leaked invitation code ID to register for Windows Ecosystem connection, there is no way to get localized versions of Windows 7 Beta or Windows Server 2008 R2 (aka Windows 7 Server edition) other than versions that provided for free official download.

Those who interested to download Language Interface Packs for Windows 7 Beta build 7000.0.081212-1400 and apply it to localize the installed system display language can use the following HTTP download links to download language packs instead. The Language Interface Packs are not specified to be MUI (Multilingual User Interface), which allows for the installation of multiple interface languages on a single system, or LIP (Language Interface Pack), which is a localized skin for localizing software in emerging or minority language markets, but most should be MUI.

Note: String in bracket is CRC value.

Download Language Interface Packs for 32-bit (x86) Windows 7 Beta

US English: x86fre_client_en-us-GB1CLP_EN_DVD.iso (0x7E8005D4)
Simplified Chinese: x86fre_client_zh-cn-GB1CLP_CN_DVD.iso (0xC8A91CD0)
Traditional Chinese: x86fre_client_zh-tw-GB1CLP_TW_DVD.iso (0x79D97687)
Korean: x86fre_client_ko-kr-GB1CLP_KO_DVD.iso (0xBBCABDAE)
Arabic: x86fre_client_ar-sa-GB1CLP_AR_DVD.iso (0xA95E7173)
German: x86fre_client_de-de-GB1CLP_DE_DVD.iso> (0xB8B06076)
Japanese: x86fre_client_ja-jp-GB1CLP_JA_DVD.iso (0x6D8F6779)
Hindi: x86fre_client_LIP_hi-in-GB1CLIP_HI_DVD.iso (0x53974B35)

Download Language Interface Packs for 64-bit (x64) Windows 7 Beta

US English: amd64fre_client_en-us-GB1CxLP_EN_DVD.iso (0x52E672BD)
Simplified Chinese: amd64fre_client_zh-cn-GB1CxLP_CN_DVD.iso (0x99B92D93)
Traditional Chinese: amd64fre_client_zh-tw-GB1CxLP_TW_DVD.iso (0x0A580CAE)
Korean: amd64fre_client_ko-kr-GB1CxLP_KO_DVD.iso (0x2327DCFE)
Arabic: Download Local Language Interface Packs for Windows 7 Beta

The ISO appears to have LIP display language packs for Australia, Brazil, Canada, China, Germany, Spain, France, UK, India, Italy, Japan, Korea, Mexico, Netherlands, Poland, Russia, Turkey, Taiwan, US, and South Africa.

32-bit: client_localpacks-GB1LCLPCKCFRE_DVD.iso (0xFCB14E84)
64-bit: client_localpacks-GB1LCLPCKCXFRE_DVD.iso (0x21195B94)

Download Language Interface Packs for 64-bit (x64) Windows Server 2008 R2 (Windows 7 Server) Beta

English: amd64fre_Server_en-us-GB1SxLP_EN_DVD.iso (0x6D5C14B9)
German:amd64fre_Server_de-de-GB1SxLP_DE_DVD.iso (0x5ABA32E3)
Japanese: amd64fre_Server_ja-jp-GB1SxLP_JA_DVD.iso (0xB26F02D7)
Arabic: amd64fre_Server_ar-sa-GB1SxLP_AR_DVD.iso (0x79466856)

Download Language Interface Packs for 64-bit (x64) Windows Server 2008 R2 (Windows 7 Server) Beta Itanium Systems

English: ia64fre_Server_en-us-GB1SIALP_EN_DVD.iso (0xE226D219)
German: ia64fre_Server_de-de-GB1SIALP_DE_DVD.iso (0x7706D664)
Japanese: ia64fre_Server_ja-jp-GB1SIALP_JA_DVD.iso (0xFDBADFAC)

The step to install additional display language in Windows 7 is pretty much the same with Windows Vista. Check out the tutorial to install additional display languages (MUI and LIP) and change the display language.

Update: Official Windows 7 RTM MUI Language Packs