Enquiries from potential PhD students and postdocs are always welcome. Please see the Department postgraduate web page for full details. You will need to get in touch with me by November if you wish to be considered for a Departmental research-council funded studentship, which covers all costs for British students but only fees for other EU citizens.
Applications from overseas (non-EU) students are also welcome, but you should bear in mind that there is relatively little funding available. There are some scholarships available (e.g. Gates), but these are usually very competitive. You should also make enquiries in your home country, to check whether there are suitable studentships that would cover your studies in the UK.
I am not in a position to provide funding for postdocs, unless a position has been explicitly advertised. If you are suitably qualified, you might consider applying for college fellowships (see the webpages of individual colleges for details): deadlines tend to fall between October and February for positions starting in the following October.
If you thinking of applying, please send a cv and a covering email telling me where your interests lie (Ed Turner - firstname.lastname@example.org).
I would encourage you to come up with your own projects, within my general area of research interests. I am currently particularly interested in insect biodiversity in tropical rainforest and oil palm plantations: the factors that determine species richness and the consequences of loss of biodiversity on the functioning of tropical ecosystems. Our work is currently mainly focused in rainforest in Sabah, Malaysia and oil palm plantations in Sabah and Sumatra, but ideas for fieldwork in any part of the world would be welcome.