I am Dutch, married to a Singaporean woman, having lived in The Netherlands and now back in Singapore, me being a PR here.
We didnot apply for a landed PR for Singapore for myself here, but applied from out of Holland. At the Singapore embassy in Brussels (or the consulate in Rotterdam), they will assist you in putting together all the needed information and filling in all papers.
I got my PR within 6 weeks after applying. Basically you need to send in all personal information on education, work history, income, taxes etc. Everything with (officially translated) copies etc.
Also, it would help if you as a Singaporean would already come to Singapore and get a job. If that job would provide you enough income to support both of you, his chances for the PR will significantly increase. This is what we did, my wife already found a job back in Singapore.
And another suggestion: It does help to get married first here...
From the feedback we have gotten from the ICA here, it is all about what the foreigner, married to the Singaporean, can bring in to add value for Singapore: skills, income and children...
If you want more information on my experiences with the PR, just send me a PM.