With the successful launch of NASA's third 'Great Observatory,' the Chandra X-ray Observatory (formerly AXAF), we are embarking on a new era of multi-wavelength science campaigns from space. To meet this challenge, the Space Telescope Science Institute (STScI) and the Chandra X-ray Center (CXC) have initiated a test program whereby proposals of a multi-wavelength nature requiring both Hubble Space Telescope (HST) and Chandra data can be submitted to either the HST Review Panel or the Chandra Review Panel. This joint activity enables proposers to avoid the 'double jeopardy' of submitting to two separate reviews. By agreement with the CXC, STScI will award up to 400 kiloseconds of Chandra observing time, and similarly the CXC will award up to 100 orbits of HST time (about one week of observing time for each observatory). The only criterion above and beyond the usual review criteria is that both sets of data are required to meet the scientific goals. We discuss the multi-wavelength allocation concept, how the process worked for HST's Cycle 9 Review and modifications expected for Chandra's Cycle 2 Review. We will also address other missions, such as EUVE, FUSE, NOAO, SIRTF and NGST that might be included in coordinated observation time allocation in the future.